The FBI DNA Laboratory: A Review of Protocol and Practice Vulnerabilities

May 2004
Office of the Inspector General

Steps in the Analysis of DNA

Step 1 - Forensis laboratory receives crime scene evidence.

Step 2 - Perform preliminary test. Do results reveal the pressence of a biological sample (blood, saliva, or semen)?

If no, return evidence to submitter. If yes, proceed to Step 3.

Step 3 - Take cuttings or swabbings from evidence.

Step 4- Extract DNA from cuttings or swabbings.

Step 5 - Amplify extracted DNA.

Step 6 - Analyze amplified DNA using capillary electrophoresis.

Step 7 - Review analyis results. Are results appropriate?

If no, At what point did the problem occur? Repeat process from that point forward (extraction, amplification, or analysis). If yes, proceed to step 8.

Step 8 - Make allele calls and prepare report.

Step 9 - Return evidence to submitter.