NATIONAL FORENSIC SCIENCE WEEK 🔬 Scientists in the Biology/DNA section of the laboratory screen items of evidence that are submitted to the Crime Laboratory Division from crime scenes to locate possible sources of DNA on these items. DNA profiles can be developed from a variety of sources including blood stains, semen, tissue, saliva, and hair roots. During DNA analysis, a DNA profile is developed from crime scene samples and known reference samples collected directly from persons of interest.