FORENSIC SCIENCE

The Crime Scene Team

Complex ReasoningIn Forensic Science

Members of the CSI Team must employ the following skills:

Deductive reasoningCommunicationLogicObservationPatienceMethodical Approach

3

How are your deductive reasoning skills?

When Mrs. Jackson came back from lunch, there were several messages on her desk. By changing each digit of the phone numbers to one of the three corresponding letters on the telephone buttons, can you determine her relationship to each caller?

(Answers are on the next slide)

4

Deductive Reasoning Answers

336-8478 dentist(222)686-2868 accountant774-6837 printer487-2263 husband247-5463 airline832-2437 teacher

5

CORPUS DELICTI

Corpus delicti (body of the crime) is a legal term that refers to the principle that proof of a crime must occur before a person can be convicted of the crime.

Therefore the CSI team must prove: that a crime occurred that the person charged with the crime was responsible for the

crime

Sources of Evidence needed for proof:Body/Victim(s)Primary and/or Secondary Crime SceneSuspect(s)

6

Crime Scene Team

The CSI Team is a group of professional investigators, each trained in a variety of special disciplines.

Team Members First Police Officer on the scene Medics (if necessary) Lead Investigator Medical Examiner (if necessary) Photographer Field Evidence Technician Note Taker Sketch Artist

7

Crime Scene Team (cont)

Although they do not actually work at the crime scene, the laboratory technicians analyze the evidence and provide answers to the investigators.

The Lab Team includes:pathologist serologist

DNA expert toxicologist

forensic odontologist forensic anthropologist

forensic psychologist forensic entomologist

firearm examiner bomb and arson expert

Document/handwriting experts fingerprint expert

8

The Role of Each Team Member

Each member of the team has a very specific job that occurs in a specific time frame. For example, the evidence technician cannot collect the evidence until the photographer has finished taking pictures and the sketch artist has completed a rough draft. This is an established protocol that must be followed at every crime scene.

9

The Protocol

A crime or suspected death has occurred, a telephone call has been placed to 911 and the police are dispatched to the scene.

Listen to real 911 calls:

http://www.911callers.com/

The First Officer at the Scene is the lead crime scene member. The acronym ADAPT explains his/her role.

10

First Officerat the Scene

A Assess the crime scene

D Detain any witnesses

A Arrest the perpetrator

P Protect the crime scene

T Take notes

11

ADAPT

1. The First Officer on the Scene will assess the scene to determine if the scene is safe, if there is a victim that needs assistance and identify all escape routes. Medics will be called if needed.

2. Next, the officer will instruct potential witnesses to remain at the scene.

3. Arrests will be made if warranted.4. The officer will secure the scene with crime scene

tape.5. After the scene is secure, the officer will monitor the

entrance and begin security log notes.

12

The Lead Investigator

The lead investigator will be the first member to work the scene. He/she has a limited amount of time to observe the scene in an untouched state.

The lead investigator determines the boundaries of the crime scene, identifies any entrances/exits and completes an initial walk-through to gain an overview of the situation and a plan for examining and documenting the scene.

13

Primary vs. Secondary Crime Scenes

The Lead Investigator may soon realize that there are other locations related to the crime scene under investigation. These locations would be secondary scenes.

A primary crime scene is the location where the offense occurred. Secondary scenes are any locations that are related and may provide evidence.

For example, in a bank robbery, the bank is the primary crime scene. The getaway car and apartment where the robbery plans were finalized are secondary scenes.

14

An Investigator’s Job According to Dr. Lee

“The wise forensic investigator will always remember that he must bring all of his life experiences and logic to find the truth. This means common sense, informed intuition, and the courage to see things as they are. Then he must speak honestly about what it adds up to.”

Dr. Henry Lee

Chief Emeritus for Scientific Services and the former Commissioner of Public Safety for the state of Connecticut

15

Crime SceneSearch Patterns

Spiral Grid

The Lead Investigator will determine will type of search pattern to implement. There are four main patterns.

16

Crime SceneSearch Patterns (cont)

Strip or Line Quadrant or Zone

17

An Outdoor Crime Scene

Many times a crime scene is located outside. While the roles of the crime scene team remain the same, the search patterns are markedly different.

An outdoor crime scene is mapped. The mapping style depends on the scene.

18

Crime Scene Mapping(outdoors)

Azimuth--uses a compass beam to determine the location of each piece of evidence

Triangulation--uses two points at the crime scene to map each piece of evidence

Coordinate or grid--divides the crime scene into squares for mapping.

Suspended Polar Coordinate--for use in mapping evidence in a hole

Baseline--set a north/south line and measures each piece of evidence from this line.

19

Photographer

Once the lead investigator has completed an overview of the scene, the photographer will enter the scene.

The photographer will begin taking wide view photographs of the scene.

20

Photographer (cont)

After the Evidence Technicians have identified and numbered the evidence, the photographer will take close photographs of each piece of evidence.

These photographs must include a ruler to provide a reference to size.

21

Evidence Technicians

The technicians will begin a through, methodical search for evidence using the search pattern determined by the lead investigator.

Physical evidence may be anything from large objects to microscopic traces. Therefore, it is important to collect objects that may carry trace evidence.

All evidence must be collected, packaged and labeled according to established protocol.

22

Chain of Custody

The evidence technicians must maintain the chain of custody.

This is a chronological documentation of each piece of evidence.

If the chain of custody is not maintained then the court case is compromised.

23

Contamination

In addition to maintaining the chain of custody, each team member has to take precautions to not contaminate the evidence.

Wearing gloves is the most important precaution.

24

The Sketch Artist

Once photographs have been taken, the sketch artist must complete a rough sketch.

The rough sketch must include: A compass heading that indicates NorthA Legend for all objects in the sketchCorrect MeasurementsPoints of entry/exitDate, time and location

25

Crime Scene Sketch Example (Rough)

26

The Final Sketch

The sketch artist will use the rough sketch as a guide when creating the final sketch.

All items on the rough sketch must be included on the final sketch.

The final sketch should be drawn to scale using graph paper or a computer.

27

Crime Scene Sketch Example (Final)

Date: August 14, 2001 Criminologist: Ann WilsonTime: 11:35 a.m. Location: 4358 Rockledge Dr

St. Louis, Mo.

A. Couch/sofa

B. Female body

C. Knife

D. Over turned Lamp

E. Chairs

F. Table

G. Fireplace

cD

E

EE

E

E

A G

F

B

28

The Sketch Artist (cont)

If any eye witnesses can give a description of the suspect(s), the sketch artist will create a composite sketch. This composite may be hand drawn or computer generated.

Of course, the sketch is only as good as the information from the eye witness.

How reliable is an eye witness?

29

Reliability of EyewitnessFactors:

The nature of the offense and the situation in which the crime is observed.

The characteristics of the witness. The manner in which the information is retrieved.

Additional factors: The witness’s prior relationship with the accused. The length of time between the offense and the

identification.

30

A TRUE EYEWITNESSCrazy Criminal

As a female shopper exited a New York convenience store, a man grabbed her purse and ran. The clerk called 911 immediately and the woman was able to give them a detailed description of the snatcher. Within minutes, the police had apprehended him. They put him in the car and drove back to the store. The thief was then taken out of the car and told to stand there for a positive ID. With that he replied, “Yes, Officer. . That’s her. That’s the lady I stole the purse from.”

31

The Sketch Artist (cont)

When skeletal remains are found and the identity is unknown, the artist may recreate an image through facial reconstruction.

This is a 3-Dimensional Technique where clay is applied directly to the skull following contours and tissue depth markers.

Often the artist has to make an educated guess in regards to the hair and eyes.

32

Case Solved Due to Facial Reconstruction

The Skull The Model Case Solved

33

The Note Taker

Notes must be taken throughout the processing of the crime scene.

The notes must include:A detailed description of the scene and evidence.The time, method and technician that discovered and

collected any piece of evidence.The names, reasons and times for anyone that enters the

crime scene.Notes may be handwritten, tape-recorded or video-

recorded.

34

The Medical Examiner

The Medical Examiner will be called when there is a corpse.

Any evidence on the corpse and the corpse itself is property of the M.E.’s office.

The M.E. will take photographs and temperatures at the scene.

The corpse will be bagged and the rest of the investigation will occur at the M.E.’s office.

35

A Lost Corpse

Occasionally the evidence indicates that there should be a corpse yet none is located at the scene.

A different approach is needed in this circumstance.

36

Cadaver Dogs

Dogs, with a sense of smell 100 times better than humans, can sometimes find what would be overlooked. They are specially trained to locate injured, lost and/or deceased individuals. They are trained as air-scent dogs or article (cloth) scent dogs.

37

Cadaver Dogs

Dogs are trained to locate human body fluids including blood, hair, teeth, urine, and semen. The dog on the left in a training exercise is trying to locate clothing with blood. Her name is Cinder.

www.moregionck9search-rescue.com

Cadaver Dogs

Looking at a crime scene, humans would probably miss something as small as this tooth. The dog found it within minutes of searching the scene.

39

After the Scene has been Processed

The evidence is delivered to the team members at the crime lab.

These forensic scientists will examine and analyze each piece of evidence.

Their findings/results will dictate how the investigates continues.

40

Investigative FlowChart

+ =

What Happened?

Why Did ItHappened?

Who DidIt?

Crime Scene Evidence Collection Witness, Suspect and Motive Development

Post Scene Evidence Processing Cause, manner, time of death

Investigative Stage Profiling

Means Motive Opportunity

Identificationand Arrest of

Suspect

41

Just A Thought

It’s not what you know that hurts you, its what you think you know and it’s not so . . . . .Mark Twain

How does this apply to forensic science and crime investigations?