In many states, sexual assault crimes are subject to statutes of limitation, which set the timeframe within which an offender can be charged with a crime. Depending on the state in which an assault occurs, statutes of limitation for a sexual assault crime vary greatly.
However, prosecutors in some states such as California, Washington and Ohio have been able to circumvent statutes of limitation, in some cases involving newly-discovered DNA evidence that could lead to the identification of a suspect. By using DNA found on evidence at a crime scene, prosecutors can elude the state’s statute of limitations and consequently bring charges against an unidentified person, essentially charging a DNA profile with a crime until the individual who matches that profile can be located. In other words, if DNA evidence is found at a crime scene even years after the crime was committed, prosecutors in some states can charge an unidentified suspect, or “John Doe”, for the crime that the forensic DNA testing links them to. Wisconsin was the first state to uphold an arrest warrant for an unidentified suspect in October 2000 with the use of forensic identity testing. The idea behind charging an unknown suspect based on his or her DNA profile is to keep statues of limitation from expiring, which would prevent offenders from escaping charges because law enforcement personnel could not identify them within the timeframe set by the statute.