forensic dna past, present, future kathy sullivan illinois state police joliet forensic science...

Forensic DNA Past, Present,

Future

Kathy Sullivan

Illinois State Police

Joliet Forensic Science Laboratory

Case Study: Jeffrey Knight

• Homicide from Kankakee County in December, 1997

• A head, hands and feet were found in a garbage bag in the woods

• Jeffrey Knight was suspected of killing his step mother, Marguerite, and disposing of her partially dismembered body

Case Study: Jeffrey Knight

• Screening results: many blood stains found, but only some were human

• DNA results: performed using DQ-alpha/Polymarker and D1S80

Case Study: Jeffrey Knight

• Stains found around the barn, on a reciprocating saw and the trunk and floorboard of a car match Marguerite Knight

• Random match probability is 2.1 billion Blacks, 5.4 million Hispanics and 5.3 million Whites

• Jeffrey Knight was convicted and sentenced to 60 years in prison (he is eligible for parole December 2027)

Case Study: Timothy Evans

• Summer of 2002

A series of night-time home invasions and sexual assaults begins in Joliet and Bolingbrook

• Media names the assailant the “Nightcrawler”

Case Study: Timothy Evans

• Evidence from one of the “Nightcrawler” sexual assaults is received by the lab in May 2003

• Underpants of the young victim are submitted to be tested for biological fluids (semen and saliva)

Case Study: Timothy Evans

• Testing indictes saliva on the crotch lining and the stain is removed for DNA analysis

Case Study: Timothy Evans

• DNA analysis yields a mixture of profiles consistent with the victim and one additional male contributor

Case Study: Timothy Evans

• Minor male DNA profile is entered into the DNA Index

• June 11, 2003 a match is reported to a sample from an Aurora case two years before

• The matching sample is a standard from Timothy Evans

Case Study: Timothy Evans

• Joliet Police Department is notified and on June 14th the suspect is arrested

• Confirmatory analysis verifies the match

• Random match probability of 1 in 20 billion Blacks, 1 in 310 billion Hispanics and 1 in 330 billion Whites

Case Study: Timothy Evans

15,17 15,17 19,21

X,Y 14,15 29,30 15,16

11,13 12,12 9,11

Case Study: Timothy Evans

X,Y

15,17 9,11

6,7 9,9 9,10

9,11

Case Study: Timothy Evans

• Timothy Evans pleaded guilty to the charges against him and was sentenced to 50 years in prison

• The DNA evidence and CODIS hit were instrumental in providing law enforcement with the link to the assailant

Advances in DNA Technologies

Yield Gel =how much DNA?

QuantiBlot =how much is human?

Advances in DNA Technologies

Quantification Procedure

Tells how much human DNA

AND how much male

DNA is in the sample

Advances in DNA Technologies

• RFLP

Advances in DNA Technologies

• RFLP

• PCR:– D1S80

Advances in DNA Technologies

• RFLP

• PCR:– D1S80– DQ-alpha– Polymarker

Advances in DNA Technologies

• RFLP

• PCR:– D1S80– DQ-alpha– Polymarker– STRs

Advances in DNA Technologies

• RFLP

• PCR:– D1S80– DQ-alpha– Polymarker– STRs– Y-STRs

Additional Technologies

• Mitochondrial DNA

On the Horizon

• Larger STR multiplexes

On the Horizon

• Larger STR multiplexes

• Automation – fluid handling systems

On the Horizon

• Larger STR multiplexes

• Automation – fluid handling systems

• High-throughput detection systems

On the Horizon

• Larger STR multiplexes

• Automation – fluid handling systems

• High-throughput detection systems

• Accreditation

Forensic DNA Past, Present, Future

• Kathy SullivanJoliet Forensic Science Lab515 E. Woodruff RoadJoliet, Illinois 60432815-740-3543

Katherine_Sullivan@isp.state.il.us