In 1987, the first man was convicted of sexual assault with the help of DNA evidence. The case was upheld on appeal the following year ( Lewis: 1988 ). In 1991, the Minnesota Bureau of Criminal Apprehension (BCA) Laboratory became the first state crime lab to identify a suspect on the basis of DNA alone. As a result of this valuable investigative resource, an otherwise unidentified rapist was found and convicted ( Ledray & Netzel: 1997 ).
The recognition of deoxyribonucleic acid (DNA) as a valuable investigative tool, and the knowledge that many rapists are repeat offenders, led to the development of the FBI Combined DNA Index System (CODIS) ( Miller: 1996 ).
The federal DNA Identification Act, included in the 1994 Crime Bill, allocated $40 million to expand DNA testing capabilities on a national basis. Today, as a result, 57 laboratories in 27 states participate in the CODIS system ( Miller; 1996 ). These databases are used for “DNA fingerprinting” in much the same way as conventional fingerprint databases are used. Genetic profiles found in semen and blood evidence are now used to link serial cases, identify offenders of multiple assaults, and exonerate falsely accused suspects ( Ledray & Netzel: 1997 ).
DNA evidence should be obtained by collecting any available blood evidence that could be from the assailant on the skin or clothing of the victim. If the survivor reports she scratched the assailant, fingernail scrapings should be collected in hopes of collecting the assailant’s blood. DNA can also be obtained by swabbing the involved orifices with a standard size cotton tip swab for sperm and seminal fluid ( Ledray & Netzel: 1997 ).
In addition, when the SANE or forensic examiner completes the evidentiary exam, blood evidence must be collected from the survivor for DNA analysis to distinguish her DNA from that of the assailant ( Frank: 1996 ).