Usually cops don't get involved with tenant-landlord issues w/o

I am not 100% about the MA rental laws. But I am pretty sure that cops usually don't get involved in tenant-landlord issues without the court orders. Since MA is the most liberal state in the county, I assume that rental laws most likely favor the tenants. Even though the woman is living there rent-free, any attempts to remove her and her stuff without the court approval is a big NO NO. That will be considered illegal procession and will be going against you should you need to file the eviction.

Try to offer some $$ to the tenants and have them move out quietly. That would be win-win for both parties.

Disclosure:

I'm neither a realtor, nor am I working in the law enforcement. Please consult professional for proper advice.