Harassment from neighbor, what legal actions do I have?

I live in Seattle, WA and I'm currently experiencing harassment from my neighboor. Im in an apartment complex that shares units with the mentaly ill. My landlord wants proof of harrsment befor taking any actions so I plan on installing a ring camera.What Im experancing is random liquids being thrown on my door, garbage and broken glass purposely being laid out in front of my door so I have to walk in it. I know who it is, and it wont stop.What steps do I need to take with the police to get this on record and eventualy what legal options do I have?