What Evidence Do The Victim Need

Forget what the victim needs you need a good criminal defense attorney. The victim is not your opponent, it is the District Attorney of your county and he needs proof beyond a reasonable doubt to win his case.
Tape recordings copies of letters witnesses, fingerprints videos wounds etc all are some of the types of evidence that would help to convict you along with your own statements so don't discuss your case with anyone who is not an attorney your priest or a doctor. Even then do not discuss the case with anyone else present unless that person works for the lawyer.

Good luck.