Evidence Sampling 1. The single most probative positive sample and the victim’s reference sample (2 total samples) will initially be selected in single perpetrator cases. 2. Upon consultation and approval of the MSFL, up to 3 positive samples (deemed most probative) and the victim’s reference sample (up to 4 total samples) in cases as outlined: • Multiple perpetrators are indicated. • Consensual intercourse within 120 hours of the alleged incident. • The victim experienced a loss of consciousness. • The victim is younger than 12 years. • Mentally challenged adults: or where no medical report is available for review. 3. The vendor laboratory will not consume more than 50% of any evidence item within a sexual assault evidence kit (SAEK) for initial analysis. • If the vendor laboratory determines that more than 50% of the original evidence is required to provide sufficient amount of male DNA to establish a potential DNA profile for searching CODIS, permission must be sought from the Mississippi Forensics Laboratory prior to proceeding with that testing. 4. The vendor laboratory will process sexual assault evidence kit (SAEKs) samples using a direct-to-DNA method (i.e., no serological analysis). DNA Extraction/Purification 1. The vendor laboratory will use the following parameters for extracting and purifying SAEK samples: • A differential extraction technique is required on all items determined to or suspected of containing sperm cells. The differential extraction will be performed using a method validated by vendor laboratory and approved by the MSFL Crime Laboratory Technical Manager. • All sexual assault evidence kit (SAEK) evidence samples will be tested using a Qiagen silica-based purification method. • Any victim, suspect, or consensual partner reference samples may be tested with any properly validated method that can reliably yield full DNA profiles as described in DNA amplification. • Once extracted for DNA, any substrates used for testing do not need to be retained. DNA Quantification 1. The vendor laboratory will use a quantitative polymerase chain reaction (qPCR) DNA quantification process that detects both total human and Y-chromosome DNA targets.
