I've had it with my entitled, complaining, disruptive tenants. They have the nicest unit I own, not the most expensive, and complain more than my 11 other units. The final straw is a leaving a note threatening violence to another tenant due to a laundry room mistake, a free laundry I might add. I have a photo of the note and video of him leaving it. 

My wife's impulse is to remove the laundry as it's relatively new and not on anyone's lease. I think that's punishing the other 3 tenants that get along, and removing value should I be showing one of those units. I want them out. But it's NJ. However they are foreign, and may not know about the protections the state provides. Recently as the lease expired (NJ automatically renews as a MtM) I asked why they did not leave if they were unhappy there. She tearfully said they weren't unhappy but just had a hard time not being picky. I told them they're not paying enough to be be as picky as they want to be and should move to a new SFH where they didn't have to deal with other people or the issues of a 120 year old house. But I did not get the impression she knew that I couldn't choose not to renew.

I have not previously given them any notice to quit, so I cannot give them a legal eviction notice based on the threat at this time anyway.  So I'm thinking to send them a registered notice to quit the premises Sept. 1st. I will explain it's not an eviction, which would leave a permanent record, but if they fight it, it will be. I don't think I need an attorney for this, but we are an LLC.

Any ideas specific to dealing with this given the lack of landlord power in NJ? Telling me I shouldn't invest in NJ will not be helpful.

If this fails I need to pressure them by raising their rent as much as I can get away with and close the laundry/storage area and refuse to let them store crap in the hallways, which will cramp their style.