Sometimes HR will back you up, sometimes they won’t and it will come back on you unfortunately. Just depends on the place really. It’s good that you’re already looking for another job.

Best thing in my opinion would be to have another job lined up and report him as you’re leaving and say you’re leaving due to his harassment. Not much they can really say to that.

If he starts going too far and making you really uncomfortable then do the same thing without a job lined up. That’s kind of a worst case scenario.

If he says creepy things to you, consider recording him. I don’t think recordings can be used as legal evidence without the persons permission in some states but it would probably be good to have just as proof of what’s going on.

Sorry you are going through this, I hope you can get it resolved soon.