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Integrative Program of Unknown Suspect Sexual Assault Case Analysis in North Louisiana

NCJ Number
Date Published
3 pages
This is the final report on a project designed to facilitate the investigation of sexual assaults in which a suspect had not been identified by the victim (i.e., unknown-suspect sexual assault).
The first study objective was to develop the capacity to routinely analyze such cases and enter the forensic DNA profile data into the Combined DNA Index System (CODIS). The second objective was to accumulate DNA profiles from suspects and local arrestees in order to build up a local database of individual DNA profiles for entry into CODIS and to compare the individual profiles with the forensic DNA profiles from the casework. To achieve these objectives, 58 unknown-suspect cases were analyzed at the North Louisiana Crime Laboratory (NLCL). Twenty-four (41 percent) had DNA profiles in the sperm fraction that came from unidentified perpetrators. The analysis of the 58 cases cleared the backlog of unknown-suspect cases at the NLCL, which resulted in the laboratory being able to analyze new unknown-suspect cases within 60 days of the initial evidence submission. The backlog reduction was achieved by using the equipment enhancements and supplies purchased with funds from this grant. The supplies and equipment realized from this grant were also used to work additional unknown-suspect cases in 2001. An additional 12 cases were completed; 4 had foreign DNA profiles. Eighteen other 2001 unknown-suspect cases are in progress, and 20 are waiting to be started. In addition to the regular unknown-suspect cases, six other unknown-suspect cases were worked separately because of a special investigative need by law enforcement agencies. These six cases were worked individually because there was an immediate need for investigative information concerning a serial rapist. All six of the cases were linked to a single perpetrator. A total of 96 unknown-suspect cases will eventually be worked by using supplies and equipment purchased under the grant. Thus, the NLCL developed and successfully used an integrated program to analyze unknown-suspect sexual assault cases. The program developed protocols that expedited analysis of unknown-suspect cases, as well as typing reference samples from suspects. In the last year since the program was instituted, it has eliminated the backlog of unknown-suspect cases, provided a rapid method of analyzing these cases, and provided a means of rapidly analyzing reference samples.

Date Published: January 1, 2001