Although “engaging in criminal activity” is an absolute grounds for eviction (RCW 59.20.080) (1) (f), and to travel under this ground one need not produce evidence of a criminal conviction (notice from a law enforcement agency constitutes sufficient grounds), proof of a criminal act is often difficult. Be advised that this same ground for termination states that notification of the seizure of illegal drugs is sufficient evidence of criminal activity. Further, the law enforcement agency has an obligation to notify the community owner if illegal drugs are seized on community property.
However, notification from a law enforcement agency is not the only means by which a community owner can establish that a tenant or guest is involved in drugs. Statements from eyewitnesses would likely also be sufficient. Once you become aware of possible drug activity put all neighbors on notice to keep careful watch and get as many people involved as are willing to observe the suspected activity. Also, call the local drug task force and put the task force on notice. As soon as you have a concrete eye witness statement or a notice of seizure, proceed directly to court to evict as no presuit notice is required.