I have a copy of the first check I wrote to him (the security deposit + two months' rent) stored on my online banking account, is this what you are referring to?
I am in the middle of trying to get my security deposit back from my landlord. The apartment I lived in was in Brooklyn, NY. Since we had an informal pay-by-the-month agreement no lease was signed. Upon agreeing to live there I handed over a check for two months rent plus the security deposit...