Kaleb Ringelstein found himself under arrest Tuesday afternoon, despite the fact that he was working with MNPD to identify and buy heroin from a dealer on their behalf. Not only did he buy the heroin for the cops, but he kept some for himself. It’s probably safe to say no one will ever sell this guy drugs again. According to a MNPD affidavit, the defendant (Kaleb Ringelstein) was working with detectives to identify a narcotics dealer. Ringelstein conducted a controlled buy of heroin from the dealer. After the deal was…