A sexual assault kit is a collection of evidence gathered from a victim by a medical professional, who is usually a specially trained nurse (Sexual Assault Nurse Examiner (SANE)). The contents of a kit generally include swabs, blood collection tubes, microscope slides, a comb, and evidence collection envelopes for hairs and fibers. The victim is swabbed for any biological evidence that may contain the perpetrator’s DNA (e.g., skin, saliva, semen). The kit can then be investigated by the crime laboratory for biological evidence, along with other crime scene evidence, such as clothing, bed sheets, toxicology reports or weapons. A single kit contains many separate items of biological evidence that could be tested to determine the identity of the suspect.
The crime laboratory will examine the evidence for traces of semen, saliva, or other body fluids on the victim’s body and clothes, using chemical and blood (serology) tests. Microscope slides will be examined for the presence of sperm. Evidence from the sexual assault kit found to have semen or other biological fluids can be kept for DNA analysis. DNA is the molecule containing our genetic code. DNA testing involves the isolation of DNA from a biological sample (e.g., blood, saliva) and the creation of a DNA profile that is a unique identifier of an individual. The sexual assault victim’s DNA will be profiled to isolate her/his DNA from any other person’s DNA found on the evidence. If there is a suspect in the case, any foreign DNA profile will be compared to the DNA profile of the suspect. For cases without a suspect, any foreign DNA profile(s) will then be compared with DNA profiles in databases such as the COmbined DNA Index System (CODIS).