Buying a House with Unauthorized Tenants

[Christina Tkacs]

I live across the street from a house with unauthorized tenants in it.  Long story very short - they're destroying the property and neighborhood, and the landlord cannot get them out.  He's dealing with real estate attorneys and sending letters to Washington State government officials daily.  I believe the holdup is that he initially allowed them to stay on a weekly basis, which technically makes them non-paying tenants and not squatters.

Not looking for comments on his mistakes!

What I'm wondering is, if I buy the house, do I have a better chance at getting them evicted?

Location is unincorporated Pierce County, Washington.