You could start by sending him a copy of the letter you sent us.
Threaten To Call The Police
If that doesn't work, have you ever really said to him straight-forwardly, "You are harrassing me, if you don't stop, I will report you to the police?"
If you haven't done that, you should. If that doesn't work, the next step is to get a temporary restraining order against him.
I think you have to go down to the County Courthouse to file this, but if it's approved, then if he ever gets near you he can be arrested.
Your Friend's Father Is Wrong
Your friend's father is wrong about the harrassing messages. Your story alone is evidence against this guy.
I suggest that if he ever calls you or emails you again (after you've told him in no uncertain terms to leave you alone) that you report him pronto.