Reporting an assault anonymously

I was wondering if anyone has any background knowledge when it comes to filing a report against someone who has sexually assaulted you.

I'm interested in filing a report against the man who raped me. I dont want to press charges or go through with any major legalities. I'm really looking to have something on file just in case this man hurts someone else he will have something against him on file already.

Is something like this possible?