There's a good reason that 'good' cops don't exist for long.
He's about to be made miserable, forced to quit (or be framed), then blacklisted from any other law enforcement position. Yeah, doing that is 100% illegal, but who's going to do anything about it?
My ex-wife was trying to be a "good" cop, but not only was she forced out with a swiftness, but she was on the secret law enforcement blacklist.
Cops don't like snitches any more than criminals do. Same difference, really.