Is he cheating?

okay so heres the story my bf had went to prison a couple months ago an then from there was sent to the halfway house well come to find out he said him an his roomie were being searchd which was random an normall for everyone well one day they searchd an found mail from his case manger which he wasnt suppose to have so tthey took there phone privliges from them that night an on monday they ended up takeing him to county some think that he slept with his case manager an thats what happend but my bf claims that he went off on his case manger for not letting him go to a job interview! im not sure what to belive can it be tru that he slept with his case manager???