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Use of Elimination Samples as a Gateway for CODIS Entry

NCJ Number
Date Published
February 2018
1 page

This document provides guidelines for submitting to the Combined DNA Index System (CODIS) "elimination" samples of DNA in sexual assault cases, which are voluntarily collected DNA samples from individuals not involved in the alleged crime, but who may have left DNA on items associated with a crime scene, but not as a result of the alleged sexual assault being investigated.


An example of such DNA may come from crime-scene evidence collected from victim underwear, body swabs, or bedding due to recent victim consensual sex with an individual not involved in the sexual assault. In order to determine which DNA sample can be narrowed to the assailant, other DNA samples obtained at the crime scene must be taken from innocent contributors in identifying which DNA is from the offender. The elimination DNA samples should not be stored or compared in the CODIS database. There is reasonable expectation that efforts will be made to collect and process elimination samples; however, with proper written documentation, the forensic unknown samples can still be entered into CODIS before the DNA comparison of the elimination sample to the forensic unknown occurs. This action enables the investigation to continue and use the benefits of CODIS. If an elimination sample is submitted later for testing, which results in an inclusion or match between the elimination samples profile and the forensic unknown profile, the forensic profile must be removed from CODIS. The procedural steps in the management of elimination samples of DNA regarding CODIS are displayed in a figure in this document.

Date Published: February 1, 2018