Neighbor harassment dispute, rights under WA state law

my neighbor been cauing problems to put to put it mildly. they would park in my spot without asking and we have a no parking in other tentants spots policy. i had to ask them to move 2 days in a row. the second day, the husband got upset and was actually confused why i would have a problem with him in my sopt and how dare i ask him to move.

anyway, he started cussing and then made a threatening gesture to which his wife put her hands up to him to stop. he eventually moved his van. the next 2 days were quiet because we didn't see each other but the third day he started staring at me in a menacing way. i ignored it. the next day, my wife was ouside and he made faces at her and mubled something. he also has flipped me off while driving away.

i complained to my landlord and she said to talk to the police since it's a civil matter. i'd like to know why she can't do anything since he's a tentant causing problems.