Summary of the Issue

A family that I am renting out to had some internal quarrels recently. In the process, a door was broken, and the tenant responsible for that property damage (herein referred to as the "problem tenant") moved out. Locks were changed and a new lease was signed that did NOT include the problem tenant. 

Today I received an email from one of the two responsible parties on the lease. The tenant informed me that his co-tenant has allowed the problem tenant to move back in AND has decided that she will not allow her co-tenant (the one who sent the email) to live in the house any longer.

The tenant who emailed me is asking that I release him from the lease if I decide to offer the parties who are now occupying the home a new lease.

That's the short version. My question is how to proceed? For those who are willing to advise me, below are more details of the situation.

Location: Idaho

The Players

    - Mr F - father of Ms D; the tenant who wrote me the email this morning. 

    - Ms D - daughter of Mr F

    - Mr P - son in law of Ms D; aka "problem tenant"

Timeline

2016-10 - Enter lease with Mr F, Ms D, and Mr P.

2017-05 - Receive detailed report from Ms D of problem with her son-in-law, Mr P. The report stated that there is an issue between Mr P and Mr F; Mr P demanded that Mr F move out. It also documented how Mr P kicked in and damaged a door. Also included is a statement submitted to the police regarding Mr P's behavior. In a subsequent email, Mr P is accused of damaging the personal property of Mr F.

2017-06 - By the initiative of Ms D, we agree to a new lease beginning on 2017-07-01. The lease is between Mr F and Ms D. Mr P has moved out. Locks are changed.

2017-07-03 - Receive email from Mr F informing me that Ms D has allowed Mr P to move back in AND that she has decided that she will not allow Mr F to live in the house any longer. Mr F has asked that I release him from the lease if I decide to sign a new lease with Ms D and Mr P, though he advises me against doing so due to their unstable history.

Ms D has not contacted me about any of these changes that Mr F has just reported to me. I will write to her asking to verify Mr F's claims, though I have no reason to doubt them. Assuming Mr P has indeed moved in, then this is a breech of the lease agreement. I no longer feel comfortable renting to this family (save for Mr F, but he would't be able to afford the rent on his own).

Please advise!