Using DNA to Solve Cold Cases
AMY HUTSELL
In 1999 , Lorenzo Williams raped three women within a 3-mile radius in Cobb County , Georgia . In each case , the victim awoke early in the morning in her own bed to find an intruder standing over her . Each woman immediately reported her assault and received a forensic medical exam to collect and preserve DNA evidence . Sexual assault kits from each attack were sent to the Georgia Bureau of Investigation Department of Forensic Sciences where DNA profiles were developed and uploaded into CODIS . The three profiles were determined to be identical . Investigators were dealing with a serial rapist , but no offender match was found in CODIS . Lorenzo Williams ’ identity remained unknown for twenty years until the Georgia Sexual Assault Kit Initiative ( GA SAKI ) Task Force re-examined cold cases . The GA SAKI Task Force is a project funded by a 3-million-dollar grant received by the Sexual Assault Unit at the Georgia Criminal Justice Coordinating Council ( CJCC ). The project , funded by the Bureau of Justice Assistance , supports the investigation and prosecution
Don ’ t forget latent prints ! Latent fingerprints are often overlooked in these cases . If they are available , they should be reviewed for database entry .
of cold case sexual assaults that have resulted from sexual assault kit backlog testing and provides advocacy for the victims in these cases . It also supports advanced DNA testing in cold case sexual assaults and homicides . In the Williams case , funds were used for this type of testing to determine the suspect ’ s identity .
Advanced DNA Testing The Combined DNA Index database ( CODIS ) was implemented in 1989 . It contains over 13 million offender profiles . It has been used in over 390,000 investigations , but investigators may not always get a CODIS hit . One of three possible outcomes occur when performing a search in CODIS :
1 . a match to a known offender ( CODIS hit ) 2 . a match to an unknown offender ( CODIS hit ) 3 . no match ( no known profile in CODIS , but DNA remains in CODIS as a potential match for a future investigation )
When there is no match or a match to an unknown offender , as in the Williams case , investigators still have options . Investigators should conduct a physical examination of any other physical evidence in agency case tracking systems . If something was missed , or if investigators think modern advances in DNA testing can be utilized , they should seek input from the crime lab . Crime lab personnel can provide input on evidence to be tested or retested and the best testing methods .
Some advanced DNA testing methods are : DNA Phenotyping predicts the physical characteristics of a suspect from DNA . It is used to help solve human remains cases , or as in the Williams case , it was used to generate possible leads . It can also be useful in narrowing a suspect list . It is used in both active and cold case investigations . Phenotyping is very detailed and includes eye color , skin color , freckling , and face shape .
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