This is more of a legal question and should be answered by an attorney, but without knowing the state, the lease, and with ALL reservations, GENERALLY, a) the lease should provide you remedies under default, b) depending on the state you can lock the tenant out of the premises provided notice of breach and default have been property given, c) commence eviction proceedings in a court of law. This may get you control of the property but may not get you any rent.
It is important that a landlords lease is properly drafted to allow the strictest interpretation of local laws and rules to insure the property can easily and efficiently be reclaimed should a tenant not pay.
CONTACT YOUR LAWYER IMMEDIATELY. A PHONE CALL TO LEGAL COUNSEL SHOULD BE YOUR FIRST STEP.
Mar 23, 2009