Although raping woman is the worst case in our society, some evil people do such thing. You may need to investigate into a rape case and have to identify the culprits who did such.
ONE
In most cases women are raped by their known-persons like as friend, relative, collogue, boss, local hooligan or someone beyond her.
TWO
If woman is raped by an unknown person, mark the way how he gets option to do that. So, record the statement of the victim about the situation of the incident and pay attention:
How she is caught, by forcedly or anyhow,
Where the incident is occurred, it is generally seen that the raping place is chosen by the rapist as a secured or better comfortable place for him. So see who has such possibility to be there.
Know the dressing type, physical condition with age of the rapist, and identify his financial or social status so that you can take an assumption.
During raping or processing, Is there any remarkable language, word, or something that might give you a sense of a clue to identify the rapist?
THREE
It is natural that when a woman is raped, she tries to resist the evil attempt of rapist. That’s why the woman’s body might be spotted, her cloths might be torn. These can be evidence. So take a photo of the spotted body and collect the torn cloth as evidence.
FOUR
The cloth might be a great important clue. As in many cases rapist’s semen might be adhered with her cloth. Then size it to medical test. DNA test is able to detect the rapist.
You can remember the scandal of Monica-bill Clinton.
So you must not wash the cloth.