Roomates Room (potentially) Taken Over By Squatters

Hello, current NYC resident.

A few weeks ago one of my 2 roomates left, and allowed her Cousin to stay in her room.

Nothing wrong with this, yet we quickly found 3 unknown people have ALSO been staying in this room.... and the roomate who let her Cousin stay in there, claims that she doesn't know who these people are. Although she has repeatedly asked them to leave, and claims they will leave soon.

I am perhaps naively trusting of people and didn't care too much, as I just assumed they were friends of the Cousin (although our 3rd roomate was uncomfortable)

As time went on they damaged a couple small things and things got a little tense.

Today we found them moving a mirror into their room. Immediately this set off red flags in my mind.

I am now afraid we are in a squatting situation and am unsure of next steps.