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Forensic DNA Education for Law Enforcement Decisionmakers

Screening Process

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Time Required to Perform Laboratory Analysis

Step 1: Screening Process

composite of three images, collecting DNA on swab, testing swab, results of swab
National Institute of Justice (NIJ) (see reuse policy).

This step entails examining the evidence and determining the location of biological evidence.6 The methods used to locate stains depend on the type of body fluid/tissue likely to be present. One of the simplest forms of evidence is a swab or similar collection device used by a law enforcement officer, health care worker, and/or crime scene technician to collect material.

Frequently, little effort is required to locate the stain on a swab. Evidence that is slightly more complex includes blood on a hard surface, such as window glass; stains on items such as clothing, bed sheets, blankets and carpet can also be challenging. These types of evidence require additional time for processing.

6 Phoenix Police Forensic Biology PDF download: 1.8MB • Visit the Phoenix Police Department »

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