My question involves a roommate in the State of: CT
I am the only person on the lease for my two bedroom apartment. When my last roommate moved out, I found a new roommate. We did not have a written agreement but when I offered him the room we discussed that the lease would run through the end of July. He agreed to stay for the duration of the lease, moved in, and a little over a month later informed me that he wanted to move out. At that point, he asked about using his security deposit for the current month's rent (after making several excuses about why he hadn't paid the rent seeing as how it was the 4th of the month). I informed him that wouldn't be possible and that I would need to find a new roommate before I could give him back his deposit since what I had been doing was using the new roommates deposit to give my last roommate the deposit.
My roommate agreed and gave me the rent for the month. I have been looking for a new roommate but have not found anyone yet. My roommate is due to move out and I am wondering if it would be legal to say that I will be using the deposit to cover this months rent since I have not found a new roommate. Or, to at least delay in giving the deposit back since it would mean that I would have to cover the entire month's rent as well as return the deposit.

