trace evidence

7/21/2019 Trace Evidence

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SUBJECT: TRACE EVIDENCE Scope of Presentation:

A. Introduction

B. Presentation of Contents: I. Hair

II. Fibers

III. Glass

IV. Paint

V. Soil and rocks VI. Tool Marks a Trace !idence

VII. S"oe Print and Tire I#pressions as Trace !idence

VIII. Blood as Trace !idence

I$. %atent Fin&erprint as Trace !idence

Prepared b':(ICA()*+ P,*+ CA(A%-A MM MBA )IAPPolice Senior Superintendent /)SC0 /B.S. CH.0Forensic C"e#ical +fficer



Trace !idence 1 an' #aterial or article found or reco!ered durin&t"e cri#e scene in!esti&ation 2"ic" #a' assist in t"e solution of a caseand t"e prosecution of t"e &uilt'.

+ne of t"e #ost co##on t'pe of p"'sical e!idence t"at an in!esti&atorand3or cri#e scene specialist 2ill encounter 2ill be trace e!idence. Tracee!idence is a &eneric ter# for s#all often #icroscopic #aterial. Tracee!idence at a cri#e scene can include suc" ob!ious t"in&s as blood "air&lass particles or paint. T"is can also include less ob!ious ite#s suc" as

#inute fibers or e!en soil. T"erefore 2e are &oin& to discuss t"e &eneralproperties of "air fibers &lass paint and soil and look at t"e !alue ofeac" as e!idence and "o2 to collect eac" of t"e# properl'.

TRACE EVIDENCE

A. Introduction



B. Presentation of Contents: I. Hair

• Hair is one of t"e #ost co##on t'pe of trace e!idencefound at a cri#e scene. (e4t to teet" and bones it isalso one of t"e #ost deca'5 resistant "u#an ele#ents.

• Structure of Hair

Structurall' a "air is co#posed of t"e tip endcuticle corte4 #edulla and bulb or root.

6. Cuticle 1 is t"e outer surface of t"e "air and 2"en

!ie2ed under a #icroscope appears co#posed of ascale5like flakes eac" o!erlappin& t"e ot"er si#ilar tot"e o!erlappin& of sin&les on a roof or scales on a fis".T"ese scales are kno2n as cuticular scales.



2. Cortex – The cortex is the inner portion

of the hir n! contins the pi"#enttion orco$orin" of the hir.

%. &e!'$$ – Is the core or center portion of

the hir shft n! (hen #"nifie!) pperss irre"'$r) spin$) chin) or contin'o's

!r* $ine of +r,in" (i!th) r'nnin" 'p the

center of the hir shft.



-ir E+i!ence



VA%7 +F HAI* AS VI)(C

T"e !alue of "air as e!idence in cri#inal cases "asbeen clearl' reco&ni8ed. Hair is seldo# conclusi!eas e!idence but in con9unction 2it" ot"er details"as pro!en to be an i#portant and essential aid to

t"e in!esti&ator. T"e in!esti&ator and cri#e scenespecialist #ust speciali8e on t"e i#portance of t"ist'pe of e!idence durin& t"e initial p"ase of t"ein!esti&ation



• T"e ori&in and te4ture of "air found at a cri#escene on a bod' clot"in& or "ead&ear of a

suspect or !icti# #a' be e4ceedin&l' i#portantas e!idence particularl' in "o#icides and se4cri#e. Hair #a' be pulled out durin& t"e cri#eand found at t"e scene or on t"e !icti#. Hair #a'be pulled out durin& an' p"'sical contactbet2een t"e suspect and t"e !icti#. Hair #a' fallout under conditions t"at t"e suspect is nota2are of and unable to &uard a&ainst. Properl'"andled b' t"e cri#e scene specialist andin!esti&ator "air #a' pro!ide e4cellentin!esti&ati!e leads and add to t"e e!identiar'

facts bein& asse#bled.



SA*CH C+%%CTI+( AS A( VI)(C A()+BTAI(I(G HAI* STA()A*)

• T"e #ost difficult task facin& cri#e scene specialistis to initiall' locate "air e!idence at t"e cri#e scene.

T"e searc" of t"e cri#e scene #ust be t"orou&"detailed and e4act. +b!ious locations to searc"include "ead&ear and clot"in& 2it" special attention&i!en to linin&s pockets and cuffs. In addition to t"e&eneral cri#e scene area ot"er areas to searc" #a'

include t"e !icti#s bod' /especiall' in se4 cri#es0underneat" t"e fin&ernails and an' up"olsteredsurfaces suc" as furniture or car seats.

SA*CHI(G F+* HAI*



C+%%CTI+( +F HAI* AS VI)(C

• Hair disco!ered at t"e cri#e scene s"ould becarefull' re#o!ed 2it" a pair of t2ee8ers. T"e "airsa#ple s"ould be placed in a clean container suc"as a pill bo4 or it #a' be folded into a piece of cleanpaper. If a pill bo4 is used t"e cri#e scene specialists"ould ensure t"at t"e entire len&t" of t"e "air is int"e bo4 and it is not crus"ed 2"en t"e lid is put on.If paper is used special care s"ould be taken toa!oid kinkin& t"e "air b' foldin&.

• After collectin& all !isible ite#s of e!idence at t"ecri#e scene t"e pre#ises are s2ept 2it" a !acuu#

s2eeper t"at "as a filter attac"#ent. T"e contents oft"e !acuu# 2ill t"en be placed in plastic ba&s andproperl' labeled.



• +f para#ount i#portance is a!oidin& conta#inationof t"e e!idence. Hair e!idence is particularl'

susceptible to cross conta#ination and t"e cri#escene specialist #ust ensure t"at e!idence &at"eredfro# t"e suspect and fro# t"e !icti# is notinter#in&led. Hair e!idence #ust be indi!iduall'

collected properl' packa&ed and labeled andproperl' separated durin& packin& for trans#ittal.



+BTAI(I(G HAI* STA()A*)S

• ac" "air found at t"e cri#e scene #ust be co#pared 2it" a

standard sa#ple obtained fro# all possible sources. Hairstandards s"ould be taken fro# t"e !icti# and all possiblesuspects. Standard "ead "air sa#ples are taken fro# #ultipleareas of t"e "ead /top side and back0 to ensure representati!es"ade and color ran&e of t"e "air.

• ;"en collectin& "air standards fro# a li!e !icti# or suspectt"e "ead and pubic areas s"ould first be co#bed before "airsa#ples are collected. Pullin& is t"e reco##ended #et"od forcollectin& "air sa#ples fro# all persons li!in& or dead. If forso#e reason t"e "air sa#ples are cut t"e cut s"ould be #adeas close to t"e skin as possible. If pets or fur are in!ol!ed in

t"e in!esti&ation "air standards s"ould also be obtained fro#t"e#.• Hair standards and sa#ples can be easil' conta#inated if t"e

cri#e scene specialist fails to use a ne2 co#b or fail to cleant"e t2ee8ers or scissors after eac" area is sa#pled



II. FIB*S

A fiber or fila#ent is the s#$$est sin"$e

'nit for#in" the sis of the texti$e ,rn. A'arn is co#pose! of n'#ero's fiers (hichre sp'n) t(iste!) or !r(n to"ether toprepre the 'nit for (e+in" or *nittin". E,rn is so#eti#es c$$e! thre! , the$,#n.



• C/ASSES 01 1IBERS

1iers #, e !i+i!e! into he fo$$o(in" c$sses:. Ani#$ – A n'#er of fiers re !eri+e! fro#

ni#$s) the #ost i#portnt ein" (oo$) si$*)c#e$3s hir) n! f'r.

2. Ve"et$e – this c$ss inc$'!es cotton) $inen) 4'te) he#p) r#ie) n! sis$.

%. &iner$ – #iner$s pro+i!e fiers s'ch s"$ss) (oo$) n! sestos.

5. S,nthetics6 Che#istr, hs pro!'ce! n'#erof fiers inc$'!in" r,on) n,$on) or$on) n!Dcron.



SA*CHI(G F+* FIB* VI)(C

• T"e location and collection of fiber e!idence at acri#e scene can be a difficult task. )ue to t"eir#inute si8e and co#position fibers #ust be sou&"tout in a t"rou&" detailed and e4actin& fas"ion. T"e

cri#e scene specialist s"ould searc" clot"in&"ead&ear and pa' particular attention to linin&spockets and cuffs. T"e &eneral cri#e scene itselfs"ould be carefull' searc"ed for all fiber e!idence

particularl' an' location t"at #a' "a!e been t"e siteof a stru&&le or assault.



VA%7 +F FIB*S AS VI)(C

•T"e !alue of fibers as e!idence in cri#inal cases "asalso been 2idel' reco&ni8ed. Fiber e!idence isseldo# conclusi!e b' itself but in con9unction 2it"ot"er details or e!idence it "as often pro!en to bean i#portant and !aluable aid to t"e cri#e scene

specialist. T"e cri#e scene specialist #ust #akee!er' effort to #a4i#i8e t"e possible use of fibers ase!idence durin& t"e in!esti&ation.



• Fiber e!idence can "elp place a suspect at t"e sceneof a cri#e. Fibers #a' un2ittin&l' be left at t"e cri#e

scene b' t"e suspect. %ater a laborator' e4a#iner#a' deter#ine t"at t"ese fibers ori&inated fro# anarticle of clot"in& t"at 2as 2orn b' t"e suspect2"ic" #a' "a!e been described b' t"e !icti# or2itnesses.

• Fiber e!idence #a' also be interc"an&ed bet2eent"e !icti# and t"e suspect particularl' durin& cri#esof !iolence suc" as rape assault or #urder. T"isinterc"an&e can also "elp pro!e t"at t"e suspect andt"e !icti# 2ere in eac" ot"ers presence. Suc"con!incin& e!idence can se!erel' attack t"ecredibilit' of a rapists alibi particularl' 2"en it isclai#ed t"at t"e !icti# 2as ne!er in "is presence.



C+%%CTI+( +F FIB*S AS VI)(CC

• Fibers are pri#aril' reco!ered fro# t"e s2eepin&s of a cri#e

scene and t"e clot"in& of !icti#s and suspects. Because fibersare !er' easil' transferred fro# &ar#ent to &ar#ent propercollection re<uires special care.

• In order for fiber e4a#ination to "a!e #a4i#u# !alue inassociatin& t"e suspect 2it" t"e !icti# or t"e cri#e scene

standards of all #aterials 2"ic" #a' "a!e been contacted b't"e suspect at t"e cri#e scene s"ould be collected. Fiberstandards s"ould be obtained fro# e!er' possible sourceincludin& clot"in& of bot" t"e !icti# and t"e suspect ru&sdrapes 2all co!erin&s furniture etc. If possible t"e entire

ob9ect s"ould be sub#itted. If t"is is not feasible obtain a lar&eenou&" sa#ple to ensure accurate co#parison.



C+%%CTI(G HAI* A() FIB* VI)(C F*+M TH S7SPCT

• ;"en a suspect is appre"ended s"ortl' after a cri#e"as been particularl' in t"e case of a rape or se4ualassault t"e suspect s"ould be re<uired to undress2"ile standin& on a clean s"eet of 2rappin& paper.;"ite is preferred "o2e!er bro2n 2rappin& paper

is acceptable. T"e paper s"ould be lar&e enou&" tocatc" an' "airs or fibers t"at #a' drop fro# t"esuspect as "e3s"e undresses. All ite#s of clot"in&s"ould be packa&ed separatel' alon& 2it" t"e paper

used durin& t"e process.



• ;"en searc"in& t"e suspects "o#e and auto#obile

do not o!erlook suc" ite#s as co#bs brus"es bedlinens and dirt' clot"es in laundr' baskets and"a#pers. All of t"ese are potential e!idencecollection sites.

• Auto#obiles belie!ed to be in!ol!ed in "it and runaccidents s"ould be carefull' e4a#ined for t"epresence of "air and fiber e!idence. Bu#pers &rillsdoor "andles and c"ro#e strips on t"e !e"icle areall pri#e locations for t"is t'pe of e!idence to be

deposited b' t"e !icti#.



III. G%ASS

• Glass 5 is nor#all' a fused #i4ture of silica usuall' in t"e for#of natural sand and t2o or #ore alkaline bases suc" as sodali#e or potas". Glass also contains <uantities of !arious ot"erele#ent and #etals present eit"er as incidental i#purities int"e basic in&redients or added to t"e# for color de&ree of"ardness "eat5resistance and ot"er specific purposes.

• T"ese in&redients are #elted in a crucible under !er' "i&"te#peratures and t"e #olten #ass is t"en eit"er rolled blo2nor #olded into desired si8es and s"apes. It #a' later bepolis"ed &round or cut for useful or decorati!e purposes or it#a' co#bined 2it" ot"er #aterials. For e4a#ple safet' &lassis for#ed b' fusin& s"eet !in'l plastic bet2een s"eets of plain&lass and boron is added to pro!ide &reater resistance to

te#perature /i.e. P're4 &lass7



VISUA/ DISTINCTI0N 01 8/ASS

• ;"en one looks at a piece of &lass t"ere are se!eraldistinctions t"at can be readil' obser!ed 2it" t"enaked e'e. T"ese include:

• Color

• T"ickness• Cur!ature /if an'0

• Surface Te4ture



• Glass is !er' uni<ue since t"ere can be t"ousandsof different for#ulas in t"e #akin& of &lass. Fro#

t"e si#ple pane &lass to t"e 2ide !ariet' of colored&lass eac" "as its o2n p"'sical properties t"at#ake it uni<ue. For e4a#ple #etals can be added to#ake t"e !arious colors:

• 6. Iron = Greenis"

• >. Copper= Bluis"

• ?. Man&anese= Bro2nis"

• @. Gold= *ub' red



VA/UE 01 8/ASS AS EVIDENCE

• Glass can "a!e relati!el' "i&" !alue as e!idencebecause of t"e identifiable !ariations in its p"'sicalproperties and #et"ods of #anufacture. T"ee!idence !alue of &lass is also en"anced b' t"e fact

t"at lar&e fra&#ents #a' fre<uentl' be p"'sicall'#atc"ed. Suc" p"'sical #atc"es are positi!e orcertain. Ho2e!er a laborator' is li#ited in t"at it canonl' conclude t"at particular &lass e!idence

consistin& of tin' &ranules "as t"e sa#eco#position as t"e ori&inal &lass. 7nless afra&#ent can be perfectl' fit into an ori&inal &lasspiece a certain conclusion cannot be reac"ed.



TH ST*(GHT +F G%ASS A() G%ASS F*ACT7*S

• It is i#portant to re#e#ber t"at t"e stren&t" of

&lass is in its surface. As soon as t"e surface ispenetrated or scratc"ed for e4a#ple usin& adia#ond tip pencil &lass 2ill tend to break alon&t"at scratc" line. +nce t"e surface is da#a&ed t"ere#ainder of t"e #aterial is easil' cracked or

fra&#ented.6. Glass al2a's breaks under tension notco#pression. It 2ill bend until t"e tensile stren&t"is e4ceeded and t"en break.

>. A focused i#pact upon &lass 2ill produce a

predictable pattern of fra&#entation.?. *adial fractures are pri#ar' fractures.@. Spiral or concentric fractures are secondar'

fractures.



• In t"e case of t2o or #ore focused i#pacts upon a&lass surface t"e fra&#entation pattern can "elp

deter#ine 2"ic" i#pact 2as #ade first. Succeedin&i#pact radial fractures 2ill stop at t"e 9uncture of t"efractures produced b' t"e first i#pact.

• Fracture patterns are uni<ue and e4a#ination canresult in !aluable infor#ation as to t"e direction ofbreakin& force. A p"'sical #atc" of t2o pieces of&lass results in an opinion t"at t"e' ca#e fro# aco##on source to t"e e4clusion of all ot"ersources.



C0//ECTI0N 01 8/ASS AS EVIDENCE

• ;"ere pieces are lar&e enou&" to fit to&et"er all

a!ailable &lass #ust be sub#itted to increase t"eprobabilit' of findin& #atc"in& ed&es.

• %ar&e fra&#ents of &lass #ust be placed in lar&econtainers t"at 2ill pre!ent furt"er breaka&e.

• In cases 2"ere t"e direction of t"e breakin& force isre<uired pieces left undisturbed in t"e 2indo2 #ustbe #arked as to t"e inside outside top and botto#and all a!ailable &lass #ust be sub#itted so t"atenou&" pieces can be fitted to&et"er to identif' t"e

radial cracks near t"e point of i#pact and t"e pointof i#pact.



• Particles of broken &lass fro# a "it5and5run !e"icleare often present on t"e !icti#s clot"in&. Man'

ti#es t"e dri!er of a "it5and5run !e"icle 2ill e#er&efro# t"e !e"icle to deter#ine 2"at 2as "it or "o2seriousl' t"e !icti# 2as in9ured. Conse<uentl'broken &lass fro# t"e accident #a' also be founde#bedded in t"e dri!ers s"oes.

• A suspects clot"in& and s"oes s"ould be collectedin a si#ilar #anner to t"e collection of fibere!idence t"at 2as pre!iousl' discussed.

• Tools s"oes and ot"er e!idence connected 2it" t"e

suspect s"ould be packa&ed separatel' and sealed.



Chrcteristics of 8$ss E+i!ence



Concentric fracture

*ad ia l Frac ture



C"aracteristics of Glass !idence



C"aracteristics of Glass !idence /contd0



8/ASS 1RACTURES:T'pes of Fractures

A. *adial fracture 1 pri#ar' fracture rese#bles t"e 2"eel radiatin&out2ard fro# t"e point of i#pact .

B. Concentric Fracture 5 secondar' fracture "a!in& t"e appearanceof circles around t"e point t"e point of i#pact connectin& one

radiatin& crack to t"e ot"er t"us for#in& trian&ular pieces of&lass.

Fro# t"e stud' of t"is t2o t'pes of fractures it is possible toderi!e t"e follo2in&:

a. P+I(T +F IMPACT 1 T"e front of t"e &lass can be deter#inedue to t"e accu#ulation of dust and dirt on t"e &lass



b. )I*CTI+( +F IMPACT 1 a bullet 2ill #ake a clear cut "ole in t"eside of entrance rat"er t"at on t"e e4it side. If a s"ot is firedperpendicularl' it 2ill &i!e a crater of unifor# flakin&. If t"e s"ot isfired at an an&le fro# t"e ri&"t t"e left e4it side of t"e &lass 2ill &i!e

#ore flakin& and !ice !ersa. )epression 2ill be produced on t"e e4itside of t"e &lass due to t"e rebound of t"e &lass. *adial fracture canbe felt on t"e e4it side and t"e concentric fracture on t"e entranceside.

c. CA7S +F F*ACT7* 1 fracture due to "eat does not e4"ibit adefinite pattern of radial and concentric fracture but arec"aracteristicall' 2a!'. T"e s"o2 !er' little stress lines 2"ereasfractures due to #ec"anical #eans s"o2 a definite pattern of radialand concentric fractures.

)T*MI(ATI+( +F TH FI*ST SH+T F*+M A S*IS +F SH+TS:

T"e radial fracture of t"e first bullet "ole 2ill end stop t"e radialfractures of t"e succeedin& bullet "oles.



IV. 9AINT

• ;"en one t"inks of paint t"e first identif'in&c"aracteristics t"at co#es to #ind is usuall' color.Color is deter#ined b' t"e use of !arious d'es or&ranules of pi&#ent in t"e paint. Aside fro# color

paint also "as a 2ide !ariet' of ot"er distin&uis"in&c"aracteristics. T"ese include its &eneralco#position i.e. oil5based acr'lic 2ater5based/late40 etc. as 2ell as its te4ture and finis" suc" as

flat se#i5&loss or &loss. All of t"ese c"aracteristicsco#bined create a !er' uni<ue paint si&nature.



VA/UE 01 9AINT AS EVIDENCE

• As pre!iousl' noted paint can be !er' distincti!e in itsc"aracteristics. %ike2ise paint in an' for# can be useful asclue #aterial in an in!esti&ation. Paint e!idence #a' be in t"efor# of a c"ip fro# a dried paint surface trace s#ear or intacton so#e ob9ect. Paint as p"'sical e!idence is #ost fre<uentl'in!ol!ed in bur&lar' and "it5and5run accident case.

• ;"ene!er a suspect tries to force entr' into a buildin& so#et'pe of instru#ent is likel' to be used. If t"e ob9ect bein& forcedis painted c"ips of t"at paint #a' clin& to t"e instru#ent bein&used and #a' also fall onto t"e suspects clot"in&. Also if t"einstru#ent bein& used is painted so#e of t"e paint #a' betransferred to t"e ob9ect bein& forced open. Transfers of paintc"ips or traces are e<uall' probable in auto#obile collisions.



C0//ECTI0N 01 9AINT AS EVIDENCE

• Paint as e!idence #a' be collected in one of t"efollo2in& for#s:

S#all flakes or c"ips Traces of o4idi8ed /c"alkin&0 paint.

S#ears fro# fres" paint An intact painted surface or ite#.



• Paint c"ips are usuall' t"e "i&"est of e!identiar'!alue pri#aril' because t"e' are #ore likel' to be

o!erlooked b' a suspect tr'in& to rid "is person orpossessions of traces t"at could link "i# to t"ecri#e. Ho2e!er re&ardless of its for# all painte!idence &enerall' "as a "i&" !alue in anin!esti&ation.

• Paint c"ips are #ost likel' to result fro# an atte#ptto force so#et"in& or as a result of an' !iolentcontact bet2een ob9ects /one of 2"ic" "as a paintedsurface0. Paint c"ips s"ould be collected !er'carefull' to keep t"e# intact. T"e lar&er t"e paint

c"ip t"e "i&"er its !alue as e!idence. C"ips #a' bepicked up 2it" t2ee8ers but a preferable #et"od isto scoop t"e# up 2it" a clean piece of paper.



0BTAININ8 9AINT STANDARDS

• In order for a cri#e laborator' to #ake a co#parison

standards or sa#ples of paint t"at "a!e a kno2n ori&in #ustbe taken. ;"en sa#ples are collected fro# an' paintedsurface t"e paint s"ould be c"ipped rat"er t"an scraped off.T"is 2ill pre!ent t"e la'er structure fro# bein& altered and 2illpre!ent t"e loss of i#portant potential points of identification.

• T"e paint standards s"ould be taken fro# t2o sources: one

fro# 2it"in an' area da#a&ed in t"e co##ission of a cri#eand t"e ot"er fro# an ad9acent unda#a&ed area. An i#portante4ception to t"is procedure is if t"e da#a&ed area is a tool#ark no paint sa#ple is taken fro# 2it"in so t"at t"e #arkdoes not &et altered. +nl' a sa#ple fro# t"e ad9acentunda#a&ed area s"ould be taken.

• In "it5and5run in!esti&ations it is i#portant t"at t"e standardsfro# t"e unda#a&ed painted area of an auto#obile be takenfro# t"e areas i##ediatel' ad9acent to t"e point or points ofi#pact but not fro# an area in 2"ic" t"e paint is corroded.ac" paint sa#ple s"ould be separatel' packa&ed and #arkedto indicate t"e e4act location of its reco!er'.



Chrcteristics of 9int E+i!ence



Chrcteristics of 9int E+i!ence&otorc,c$e Cr crsh in S(e!en



V. S+I% A() *+CS Soils and rocks !ar' in different locations t"rou&"out t"e 2orld.

)ifferences can also be found 2it"in s#all local areas. T"e

differences bet2een t2o t'pes of soil suc" as sand and cla' #a'be easil' reco&ni8ed. Ho2e!er detailed differences and si#ilaritiesbet2een sa#ples of si#ilar soil or rocks can onl' be detected b'<ualified laborator' c"e#ists.

Value of Soil and *ocks as !idence Soils rocks and ot"er #inerals #a' be found:

6. +n t"e suspect.

>. +n t"e suspects s"oes.

?. on t"e suspects clot"in&.

@. In t"e suspects !e"icle.D. +n tools used in t"e cri#e.

E. At t"e scene of t"e cri#e.

. +n t"e !icti#.



T"ese #aterials can pro!ide !aluable circu#stantiale!idence. Ho2e!er suc" e!idence is often o!erlooked

because t"e in!esti&ator or cri#e scene specialist is neit"era2are of its potential !alue nor of t"e laborator' ser!icesa!ailable to #ake co#parisons.

Soil cannot be positi!el' identified as co#in& fro# onesource to t"e e4clusion of all ot"ers but t"e laborator'e4pert can associate <uestioned soil 2it" a #ost probablesource conclude t"at a source cannot be eli#inated or t"ata point or area could not be t"e source of t"e <uestionedsoil. T"ese conclusions "a!e pro!en e4tre#el' !aluable inpro!idin& cri#inal cases.



Searc"in& for Soil and *ock !idence:

Soil and rock e!idence is #ore likel' to be found 2"en t"ecri#e 2as co##itted outdoors or 2"en t"e suspect 2alkedor dro!e a !e"icle on unpa!ed &round. Clot"in& s"oes andot"er personal belon&in&s t"at appear to contain soil rockparticles &ri#e dust #ud or t"e like s"ould be sei8ed ase!idence and indi!iduall' packa&ed.



Soil and rock e!idence can be deri!ed in t"efollo2in& 2a's:

6. T"e suspect #a' carr' and lea!e s#all a#ounts of rockand soil at t"e cri#e scene.

>. T"e suspect #a' pick up soil and rock #aterials at t"ecri#e scene.

?. T"e suspect #a' bot" lea!e and pick up soil and rock

e!idence.@. In a "it5and5run accident t"e suspect or "is !e"icle #a' pick up

and lea!e soil and rock e!idence. T"e i#pact of t"e collision #a' dislod&e dirt and #ud t"at "ad accu#ulated on t"e undercarria&e of t"e suspect !e"icle. Suc" particles can be

found on t"e road or on t"e bod' or clot"in& of t"e !icti# 2"o2as struck b' t"e !e"icle. T"e suspects !e"icle #a' also runoff t"e road and in doin& so pick up #ud and on its tires and

undercarria&e t"at can pro!e t"e !e"icle 2as at t"e accidentscene.



Selection of Soil and *ock Standards

T"e cri#e scene specialist s"ould al2a's obtain sa#ples of rocks

and soil fro# t"e cri#e scene to be used as standards forco#parison 2it" like substances t"at #a' co#e fro# a suspect.

ac" sa#ple s"ould consist of appro4i#atel' t2o tablespoons ofsoil. ;"en takin& t"e sa#ple it is usuall' not necessar' to &odeeper t"an to of an inc". Ho2e!er if a footprint tire track or

ot"er indentation in <uestion penetrates into soil t"at is differentfro# t"e topsoil it #a' be necessar' to obtain a sa#ple of bot" t"etopsoil and t"e subsoil.

If soil and rock e!idence are found on a suspects s"oes a

co#parison sa#ple s"ould be taken fro# t"e portion of t"efootprint left at t"e cri#e scene correspondin& to t"e area on t"es"oe on 2"ic" t"e e!idence 2as found. Co#parison sa#pless"ould be taken fro# a footprint tire track or ot"er indentationonl' after a plaster cast "as been #ade



Soi$ s#p$es in $



VI. Too$ &r*s s Trce E+i!ence

• Tool #ark is t'pe of e!idence t"at in!ol!eco#parisons of kno2n standards !ersus t"eunkno2n. T"e #anner in 2"ic" t"e e4a#inations areconducted in t"e laborator' is often si#ilar. T"e

cri#e scene specialist #ust not onl' be a2are of t"e2ide arra' of bot" t'pes of e!idence but also befa#iliar 2it" t"e proper #et"ods of collectin& it forsubse<uent co#parison purposes.



. Tool#arks

Cri#es a&ainst propert' fre<uentl' in!ol!e t"e useof a tool in order for t"e cri#inal to &ain entr' intot"e pre#ises b' appl'in& force 2it" t"e tool. T"ese

tool#arks can be "i&"l' identifiable and be of&reat e!identiar' !alue.



• )efinition.

a. Tools 1 an' ob9ect capable of #akin& an i#pression onanot"er ob9ect. 4a#ples: a4es kni!es c"isels cro2bars

pliers cutters and drill bits.b. Tool#arks 1 an' i#pression cut abrasion or &ou&e left b' a

tool after co#in& in contact 2it" an ob9ect.

T2o />0 General T'pes

6. I#pressions 5 are t"ose #arks in 2"ic" onl' t"e&eneral for# and si8e of t"e tool are apparent. ;"en a tool ispressed into so#e t'pe of #aterial it produces a ne&ati!ei#pression. T"ese ne&ati!e i#pressions or #arks #a' not#ake a definite identification of t"e tool possible. Ho2e!ert"e' can ser!e as a &uide 2"en it is necessar' to decide

2"et"er or not t"e tool of a suspect could "a!e produced t"e#arks.



>. Striations 1 are t"ose #arks in 2"ic" peculiarc"aracteristics or irre&ularities of t"e tool arereproduced in t"e for# of identifications or

striations. T"ese #arks are t"e #ost !aluable ase!idence since t"e' can so#eti#es positi!el'identif' a particular tool to t"e e4clusion of allot"ers.



-o( Too$#r*s re Crete!

6. Co#pression 5 is a static identification #ade b'

blo2s usin& a tool /e.&. "a##er #arks5sled&eball pen cla2 scre2dri!er pr' #arks opposed 9a2 #arks #ade b' pliers bold cutters pipe2renc".0

>. Friction 1 is a d'na#ic #ark #ost often lea!in&

striations #ade b' t"e uni<ue ed&e irre&ularities ofa particular tool /e.&. s"ears scre2dri!ers kni!esa4es etc.0

?. *epetition5 is t"e repeated d'na#ic #arks left b'tools suc" as files or sa2s. T"ese are !er' difficultto identif' because of t"e &reat nu#ber of teet"and t"e confusion of #arks left.

@. Co#bination 1 often tool can lea!e a co#binationand friction #arks.

E i! ti V $ f T $ *



E+i!entir, V$'e of Too$#r*s

6. Class C"aracteristics5 Tool#arks left at t"e scene of

t"e cri#e usuall' 2ill re!eal #icroscopicc"aracteristics t"at can "elp re!eal t"e classc"aracteristics of t"e tool t"at 2as used. T"e classc"aracteristics of a tool are usuall' considered todistin&uis" it functionall' fro# anot"er. T"ereforescre2dri!ers #a' be considered as a class part fro#cro2bars since t"e' "a!e different intendedfunctions. T"e class c"aracteristics of tools ser!e asa screenin& de!ice in cri#inal in!esti&ations and

allo2 one to narro2 t"e field of searc" 2"ic" isespeciall' !aluable in ac"ie!in& positi!eidentification of t"e tool t"at left t"e i#pression.



>. Indi!idual C"aracteristics 1 Tools t"at are si#ilar inclass c"aracteristics are often <uite different in t"eir

indi!idual c"aracteristics. T"ese indi!idualc"aracteristics are deri!ed fro# t"e processes usedto produce t"e tool and t"e #anner in 2"ic" t"e tool"as been used. +ften s#all burrs or nicks 2ill

de!elop on t"e bit of t"e scre2dri!er producin&indi!idual c"aracteristics of t"at tool. If t"e #aterialsub9ected to t"e tool#ark is soft enou&" it 2illretain #inute i#pressions or striations reflectin&t"ese indi!idual c"aracteristics.

S hi f T $ ! T $ *



Serchin" for Too$s n! Too$#r*s

6. Searc"in& for Tool#arks5

T"e cri#e scene specialist s"ould #ake aconscientious effort to t"orou&"l' e4a#ine t"escene of a cri#e to deter#ine if an' tool#arks2ere left b' t"e perpetrator. It is also i#portant fort"e cri#e scene specialist to searc" for an'e!idence of a broken tool t"at #a' "a!e been leftbe"ind. If pieces are located t"e' #ust bereco!ered since t"e' can beco#e !aluablee!idence 2"en t"e tool and suspect are located.



Cri#e scene specialists s"ould ensure t"at t"e' look in t"efollo2in& areas for potential tool#arks:

6. )oors 1 Around t"e lockin& #ec"anis#s pa'in& particular

attention to t"e 2ood of t"e doorfra#e and 9a#b.>. ;indo2s 1 +n t"e botto# ed&e of t"e 2indo2 t"e sill and

fra#e2ork of t"e 2indo2 9a#b.

?. Safes 1 All around t"e door lockin& #ec"anis# and "in&es.

@. )ra2ers of desks filin& cabinets or ot"er secured dra2ers 1 Pa'particular attention to t"e area around an' locks as 2ell as t"e 9oinin& ed&es of eac".

D. ;ire fences e4"ibitin& cuts5 Co#pression #arks fro# t"e cuttin&de!ice are often <uite noticeable.

E. Cut locks5 Brass locks are particularl' &ood at retainin&co#pression #arks fro# t"e cuttin& tool due to t"e soft natureof t"e #etal.



>. Searc"in& for Tools T"e cri#e scene s"ould be searc"ed for an'

ob!ious tools t"at 2ere left be"ind as 2ell as toolsreco!ered fro# suspects. ac" tool located s"ouldbe e4a#ined carefull' and treated as potentiale!idence. T"ese tools "a!e t"e potential to link t"esuspect 2it" t"e cri#e scene dependin& on 2"ere

t"e' are located.?. *epetiti!e Tools Cri#e scene specialists s"ould pa' attention to

repetiti!e tools t"at #a' "a!e been left be"ind orlater reco!ered fro# a suspect. T"e' s"ould look

carefull' for t"e follo2in&:a. Material bet2een t"e teet" of files or sa2s.b. Separation of teet".

Co$$ectin" Too$#r* E+i!ence



Co$$ectin" Too$#r* E+i!ence

6. P"oto&rap"' 1 Before an' atte#pt to collecttool#ark e!idence it s"ould first be p"oto&rap"ed

in its ori&inal state. It is crucial t"at t"e tool#ark isper#anentl' recorded before is crucial t"at t"e an'atte#pt is #ade to replicate or reco!er.

>. +ri&inal State 1 ;"ene!er possible e!er' effort be#ade to collect tool#ark e!idence in it ori&inal

state. Mo!eable ob9ects suc" as cas" re&isterss#all safes and cas" bo4es offer little difficult'since t"e #arks can be collected b' reco!erin& t"eentire ob9ects.

So#eti#es t"e entire ob9ect cannot be reco!ereddue to its si8e or construction. Marks found on a2indo2 fra#e or door 9a#b can so#eti#es bereco!ered b' re#o!in& t"e da#a&ed portion of t"eob9ect particularl' 2"en t"e "o#e or businesso2ner needs to replace it.

? C ti T l k



?. Castin& Tool#arks ;"en its i#practical to collect an ite# containin& a

tool#ark in its entirel' t"e cri#e scene specialist

s"ould consider usin& castin& procedures toreplicate t"e tool#ark. Makin& casts of tool#arke!idence 2ill pre!ent t"e te#ptation to directl' placereco!ered tools into tool#arks to !erif' a #atc".Great care s"ould be used to ensure t"at t"e ori&inaltool#ark is not da#a&ed or altered in an' #anner.

T"e cri#e scene specialist s"ould ne!er put a tool int"e #ark 1 not onl' 2ill it conta#inate t"e e!idencet"e potential e4ists to actuall' alter or destro' t"eori&inal tool#ark and possibl' conta#inate t"e toolb' transferrin& trace e!idence fro# t"e tool#ark to

t"e suspect tool. 7se silicone rubber /dental silicone #a' be used<uite successfull'0 for best result. Casts s"ould beused to #ake co#parisons 2it" tools or test #arks.



C" t i ti f T l M k



C"aracteristics of a Tool MarkCorrespondin& Tool Mark %eft at t"e Scene of a Cri#e

C" t i ti f T l M k / td0



C"aracteristics of a Tool Mark /contd0Face of a Co##on Ha##er



VII.Shoe print n! Tire i#pressions

s Trce E+i!ence



S"oe print and tire i#pression e!idence is anot"er

for# of !aluable p"'sical e!idence t"at is oftenencountered at cri#e scenes. Since cri#inals #usteit"er 2alk or dri!e to and3or fro# t"e cri#e scene its"ould be reasonabl' assu#ed t"at traces of

i#pression e!idence 2ill be left be"ind. T"ereco&nition collection and e4a#ination of t"isi#pression e!idence can pro!ide irrefutable proof oft"e presence of an indi!idual or a !e"icle at a cri#escene or in contact 2it" a !icti#.



The V$'e of Shoe 9rint n! Tire I#pression

E+i!ence

T"e c"aracteristics of i#pression e!idence t"at allo2for a co#parati!e e4a#ination lar&el' consist oft"ree /?0 ele#ents:

6. )esi&n C"aracteristics

T"is is t"e basic pattern of t"e s"oe sole or tiretread desi&n. T"ese patterns are usuall' patentedalt"ou&" ille&al copies or knock5offs are oftenreproduced0 and are so#e2"at specific to a

#anufacturer. 7suall' #an' s"oes or tires areproduced t"at "a!e t"is basic pattern desi&n.



>. ;ear patterns As t"e s"oe or tire is 2orn or used on a !e"icle t"e

pattern area 2ill 2ear do2n as erosion of t"e treador sole #aterial takes place. T"is 2ear pattern&enerall' follo2s a so#e2"at nor#al pro&ression.Ho2e!er ot"er factors suc" as t"e &ait or 2alkin&pattern of an indi!idual 2earin& t"e s"oes or t"e

front end #isali&n#ent of t"e tires on a !e"icle ort"e under or o!er inflation of t"e tires 2ill "a!e aneffect on t"e o!erall 2ear pattern. Alt"ou&" nor#all't"e 2ear pattern alone 2ill not pro!ide t"e basis forpositi!e identification it does i#part so#e

indi!idualit' or a&ree#ent bet2een t"e co#parisonof t"e kno2n s"oe3tire and t"e unkno2n found at t"ecri#e scene.



?. Accidental C"aracteristics

)urin& t"e nor#al use of a s"oe or tire so#eda#a&e suc" as s#all cuts and nicks are i#partedon t"e tread or pattern surface. T"esec"aracteristics are kno2n as accidental and occurrando#l' on all tire and s"oe desi&ns co##onl' inuse. Assu#in& t"e a&ree#ent of t"e desi&nc"aracteristics and 2ear patterns t"e #atc" ofaccidental c"aracteristics #a' allo2 for t"e positi!eidentification of a particular s"oe or tire as "a!in&

#ade a particular i#pression.

T,pes of Shoe 9rint n! Tire I#pression



T,pes of Shoe 9rint n! Tire I#pression

6. T2o )i#ensional

T"ese i#pressions are usuall' found on a "ardsurface t"at "as been contacted b' a s"oe sole ortire tread t"at "as left be"ind or re#o!ed residue

or ot"er #aterials. )etails of t"e sole or treadpattern can be seen on t"e surface . I#pressionst"at are #ade 2"en t"e s"oe or tire "as depositedor left be"ind residue are kno2n as positi!e

i#pressions. (e&ati!e i#pressions occur 2"enpree4istin& residue is re#o!ed 2"en contacted b'a s"oe sole or tire tread.



2. Visi$e 9rints

T"ese prints /i#pressions0 are usuall' readil' apparent an are

nor#all' disco!ered durin& t"e preli#inar' sta&es of t"e cri#escene response. ;"en a s"oe or tire co#es in contact 2it"eit"er a li<uid substance suc" as paint &rease blood 2ater ora dr' residue suc" as fire e4tin&uis"er po2der flour safeinsulation and t"en contacts a "ard surface a !isible print 2ill

be deposited. 7suall' t"ese prints are fairl' stable and can bereco!ered durin& nor#al cri#e scene processin& as lon& ast"e' are ade<uatel' protected fro# inad!ertent destruction. T"ee4ception 2ould be if t"e print consists of 2ater or a !olatileli<uid /&asoline0 t"at #a' <uickl' e!aporate docu#entation

and reco!er' s"ould t"en be an i##ediate priorit'



%. /tent 9rints

T"ese prints /i#pressions0 are usuall' #ade 2"enrelati!el' clean dr' s"oes deposit or re#o!e a !er't"in la'er of residue suc" as dust. Because t"esedeposits occur in trace <uantities and often lackcontrast to t"e surface t"e' #a' not be readil'

!isible and are often o!erlooked. Searc"in& t"e cri#escene 2it" a stron& obli<ue li&"t source or #akin& ablind searc" 2it" an electro5static liftin& de!ice #a're!eal t"ese i#pressions.

5 Th !i i $



T"ese i#pressions are created 2"en a s"oe sole ortire tread contacts t"e &round or a soft surface 2it"sufficient force to cause a defor#ation of t"atsurface. T"e resultant i#pression is a ne&ati!ei#pression of t"e s"oe sole or tire tread and 2ill

re!eal len&t" 2idt" and dept" c"aracteristics.T'picall' t"ese i#pressions 2ill be p"oto&rap"edt"e surface 2ill be prepared /stabili8ed0 for castin&t"e i#pression 2ill be rep"oto&rap"ed and a plaster

cast 2ill be #ade.

5. Three6!i#ension$



PH+T+G*APHJ

T"e p"oto&rap"ic docu#entation of s"oe print andtire i#pression e!idence is essential to per#anentl'record all c"aracteristics and details of t"e

i#pression. In addition t"e location of i#pressione!idence at t"e cri#e scene #ust be recorded toallo2 for t"e future interpretation of directionalit't"e rele!anc' of relations"ips to ot"er ob9ects and

ite#s of e!idence etc.

CASTI(G



A cast is a t"ree5di#ensional properl' oriented life5si8edreproduction of t"e positi!e i#a&e of an i#pression #akin&

ob9ect. Casts s"ould al2a's be #ade of t"ree5i#pressions tosupple#ent t"e p"oto&rap"s.

CASTI(G

6. I#pressions in sand and soil.

a. )ental stone is t"e preferred castin& #aterial and 2illpro!ide superior detail and tensile stren&t" o!er plaster5of5paris or ot"er castin& #ediu#s.

b. Prior to castin& re#o!e lea!es t2i&s or loose ob9ects t"at#a' "a!e fallen into t"e i#pression. )ebris t"at is e#beddedin t"e surface of t"e i#pression s"ould re#ain .

c Preparation of t"e surface



6. Spra' 2it" a fi4ati!e

T"e i#pression s"ould be &entl' spra'ed 2it" a fi4ati!esilicone spra' aerosol /suc" as "airspra'0 to #ake t"esurface i#per!ious to t"e li<uid dental stone t"at 2ill be

poured in. If t"e i#pression #ediu# is a !er' loose orporous #aterial it is desirable to spra' se!eral li&"t coats of&ra' pri#er paint o!er t"e i#pression. A&ain bein& carefulto a!oid disruptin& t"e i#pression surface 2it" t"e force oft"e aerosol propellant.

>. P"oto&rap" t"e i#pression a&ain at t"is point as #ore detail#a' be "i&"li&"ted b' t"e addition of t"e fi4ati!e a&ent.

c. Preparation of t"e surface

d Preparation and pourin& of t"e castin& #aterial



d. Preparation and pourin& of t"e castin& #aterial

6. T"e castin& #aterial /)ental stone or die stone0 s"ould beread' for use in a disposable plastic Kiploc ba& /L $ 6>si8e0. A pre #easured portion of t2o pounds s"ould bedi!ided into eac" ba&.

>. Add 6> ounces of 2ater to t"e ba& and reseal. Massa&e t"e#i4ture t"rou&" t"e closed ba& until it is t"orou&"l' #i4ed2it" no lu#ps and "as t"e consistenc' of pancake batter.

?. T"e castin& #aterial s"ould be poured on t"e &roundad9acent to t"e i#pression and allo2ed to allo2 to flo2

into t"e i#pression. Continue to add castin& #aterialcontinuousl' until t"e i#pression is full and o!erflo2s.



@. Case and i#pression identifies can be scratc"ed into t"e

back of t"e cast as it be&ins to "arden.

D. Allo2 at least > #inutes for t"e cast to "arden beforecarefull' atte#ptin& to lift it. )o not atte#pt to clean an'dirt or ot"er #aterials t"at are ad"erin& to t"e underside of

t"e cast at t"is point.

E. Allo2 t"e cast to cure for at least @L "ours beforepacka&in& it in paper for stora&e or s"ip#ent to a forensiclaborator'.



C"aracteristics of a S"oe Print

S"oe Print



S"oe Print4a#ple of a S"oe Print T"at ;as %eft on a Fres"l' Painted

Step Stool at a Bur&lar' Scene

Co##on Tire I#pression



Co##on Tire I#pression

P"oto&rap"in& S"oe N Tire I#pressions



P"oto&rap"in& S"oe N Tire I#pressions

Castin& a S"oe I#pression



Castin& a S"oe I#pression




T"e #ain function of t"e blood is transportin&o4'&en nutrients and 2astes t"rou&"out t"ebod'. Blood is appro4i#atel' LO of t"e bod's2ei&"t. It consists of t"e li<uid portion calledplas#a /about DDO of t"e total blood !olu#e0 andt"e for#ed ele#ents 2"ic" are t"e red blood

cells /er't"roc'tes0 t"e 2"ite blood cells/leucoc'tes0 and t"e platelets /t"ro#boc'tes0T"e "e#o&lobin found in t"e red blood cells isresponsible for transportin& o4'&en to tissues

and carbon dio4ide to t"e lun&s. Seru# is t"eclear li<uid t"at separates 2"en blood is allo2edto clot.




I#portance For t"e Stud' of Blood

6. As circu#stantial or corroborati!e e!idence a&ainst or infa!or of t"e perpetrator of t"e cri#e.

>..For disputed parenta&e

?. )eter#ination of t"e cause of deat" and t"e len&t" ofti#e t"e !icti# sur!i!ed t"e attack.

@. )eter#ination of t"e direction of t"e escape of t"e !icti#or t"e assailant.

D. )eter#ination of t"e ori&in of t"e flo2 of blood.

C"aracteristics of Blood Spatter !idence



p

I; /tent 1in"erprint s Trce



I; /tent 1in"erprint s Trce

E+i!ence



T"e pri#ar' precaution in all cases is of courseto pre!ent addin& fin&erprints to t"e e!idence and topre!ent destro'in& t"ose prints alread' present.

Man' of t"e fin&er prints sub#itted 2ill be onpaper / on docu#ents for e4a#ple0 or on &lass or#etal surfaces.

1i i t E i!



1in"erprint E+i!ence

1i i t E i! ti !



1in"erprint E+i!ence6 contin'e!

1in"erprint E+i!ence contin'e!



1in"erprint E+i!ence6 contin'e!

TH+*J +F T*A(SF*



;"en t2o ob9ects co#e into contact t"ere 2ill fre<uentl' be atransfer of s#all a#ounts of #aterial fro# one to t"e ot"er.T"us 2"en suspects co#e in contact 2it" t"e !icti# andob9ects at t"e cri#e scene t"e' fre<uentl' lea!e be"ind tracesof t"e#sel!es and take 2it" t"e# traces of an' ob9ectstouc"ed. Materials transferred in t"is 2a' are nor#all' referredto as T*AC VI)(C.

%ocards %a2 or Principle%ocards Principle su##ari8es t"e t2o 2a' transfer of tracee!idence as:;"en A co#es into contact 2it" B so#et"in& fro# A is

transferred to B and !ice !ersa.i.e. e!er' contact lea!es a trace.



THANK YOU

AND

GOD BLESS

trace evidence

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