DNA evidence from crimes like sexual assault can be found at the crime scene, on the victim's body, in the victim's clothing, and in other personal objects. You can choose to have a sexual assault forensic investigation, sometimes known as a "rape kit," if you want to retain potential DNA evidence and receive urgent medical care. These kits can also be used for legal means.
Rape kits include:
Bags and paper sheets
Blood samples related materials
To prepare for an exam, it is best to not shower, use the bathroom, change clothes, comb hair, wash hands,