My question involves landlord-tenant law in the State of: New York

One month ago I subleased my half of a two-person lease in Brooklyn. The other tenant on the lease lives in the apartment with the sublessee. I am out of the country for an extended period of time, and my friend (the other tenant on the lease) has just contacted me to tell me he has serious issues with the new tenant.

Allegedly there is a third person who is residing in the room (sublessee's boyfriend) who also uses illegal drugs. My friend does not feel safe in the house with this third person, who often brings other strange people over. The sublessee and her boyfriend have also allegedly broken some furniture in the house and done some other damage to property.

I have no problem evicting them and allowing my friend to find a new roommate, however the sublessee has signed a sublease and does not seem to be in any breach of the terms of the sublease or the original lease except for the third party staying too long.

The landlady has apparently been unresponsive to the issue and is allowing my friend to handle it.

My questions are: how can I go about evicting this person (remember I am out of the country), do they need to be in clear breach of the lease or sublease to be evicted or can I do it without demonstrating that (is illegal activity grounds to evict?), and what rights does my friend have as the co-tenant? I need these people out immediately.

Also, will it help to call the police if my friend sees illegal drug use in the apartment or would this make matters worse?