A former inmate who was Jeffrey Epstein 's suicide-watch companion in a New York jail says the convicted pedophile definitely killed himself ... telling TMZ the guy in the cell next to Epstein heard him ripping up bedsheets to hang himself. Bill Mersey -- who was locked up with Epstein back in the day at the since-shuttered Metropolitan Correctional Center -- joined us on "TMZ Live" Thursday, and we asked him about the alleged Epstein suicide note, which was just released . Bill spent hours