When a perpetrator commits an act of nonconsensual sexual contact, they leave behind DNA—on the survivor’s body, clothing, or personal items. Since every person’s DNA is unique (except for identical twins), forensic experts can use it to help identify perpetrators and hold them accountable.
How DNA Evidence Gets Collected
If you’ve experienced sexual violence, a sexual assault forensic exam (SAFE) can help protect your health and preserve crucial evidence—even if you’re unsure about reporting the assault to law enforcement. (SAFEs are also known as “rape kits.”)
Why Consider a SAFE?
- Your health matters. A trained sexual assault nurse examiner (SANE) will check for injuries, provide medical care, and offer guidance on next steps for your well-being.
- Justice matters. Whether you decide to report the crime now, later, or never, DNA collected during a SAFE can be used as evidence if you ever pursue legal action.
How DNA Helps Identify Perpetrators
DNA can be a game-changer in court. Unlike witness testimony or circumstantial evidence, jurors often view DNA as concrete proof. In fact, 73% of jurors expect to see DNA evidence in a rape trial. (1)
When a crime lab uploads a DNA profile to the National DNA Index System (NDIS), investigators can compare it to a database of over 17 million offender profiles through the FBI’s CODIS program. This helps link repeat offenders to crimes nationwide—potentially preventing future assaults.
By participating in a SAFE, you may help identify repeat offenders.
After DNA Evidence Is Collected
After a SAFE, what happens to the collected evidence depends on the laws in your state. Each state has different policies for processing and storing evidence kits. A forensic nurse, victim advocate, or police officer can explain your state’s laws on:
- How much time you have to report to the police
- How long evidence is stored
- What happens to untested kits
If You Don’t Want To Involve Law Enforcement
If you’re not ready to talk to the police, that’s okay. You may still obtain a SAFE. What happens next depends on which state you’re in.
- In most states, survivors can choose to have evidence collected without immediately involving law enforcement. Their kits are stored, unprocessed, by either law enforcement, the hospital, or the SANE. Each state provides a limited window of time for the survivor to report to the police and get their kit tested.
- In some states, forensic kits can be tested without opening a police case. These kits are typically known as “restricted kits.” Law enforcement may be contacted to retrieve the kit, but an investigation won’t be opened unless the survivor decides to proceed.
In a few states, DNA reporting is mandatory by law, meaning law enforcement must be notified whenever a SAFE is conducted. In these states, every kit is tested and entered into the system regardless of the survivor’s wishes.
If You Want To Report to Law Enforcement
If you’re ready to talk to the police, your kit will typically be transferred to law enforcement and sent to a crime lab for analysis.
- If you’ve identified a suspect, the lab will compare the DNA evidence to that individual’s profile.
- If the perpetrator is unknown, the DNA may be checked against the National DNA Index System (NDIS), a database maintained by the FBI that contains millions of offender profiles.
The Statute of Limitations: Timing Matters
The statute of limitations sets a time limit for pressing charges against a perpetrator. This limit varies by state, type of crime, and the survivor’s age. Once this window closes, law enforcement may no longer be able to pursue charges—even with substantial evidence.
How DNA Gets Added to the National Database
If a forensic kit is tested by a crime lab, the resulting DNA profile will be entered into NDIS for potential matches. However, in states where restricted kits are allowed, DNA is not added to the system unless the survivor later decides to report.
For many survivors, restricted kits provide an option to receive medical care and preserve evidence without the immediate pressure of engaging with law enforcement. This flexibility ensures survivors have time to decide what’s best for them.
Medical Disclaimer: Please note that the content on this site does not constitute medical advice, and RAINN is not a medical expert. If you have further questions after reading this information, please contact a local healthcare professional or hospital.
SOURCES
(1) National Institute of Justice. (March 2008.) The ‘CSI Effect’: Does It Really Exist?
(2) Federal Bureau of Investigation. (February 2024.) CODIS-NDIS Statistics.
Last updated: July 15, 2025