They hired armed private security, which evacuated the first night because they got their feelings hurt by "verbal attacks" and were not allowed to engage. I'm guessing this will escalate things. Next, the city will send in someone with a firmly-worded letter telling the criminals how angry they are that they won't leave.
Maybe someone should tell Seattle officials a little secret about criminals - generally, they don't respect you unless they fear you. Now, take that concept and run with it.
Mull it over and see what you come up with. Here's a hint, it involves some measure of violence, arrest, trial and punishment. It's often been called "law enforcement".
Maybe they could consider trying THAT.