Jade (1995). Kyle Medford, an art collector, was hacked to death. He's a go-fer for the politically powerful, introducing them to women but they don't know he's secretly taping them. D.A. David Corelli (David Caruso) is up for re-election, takes on the high profile case. It's a sex thriller but there was nothing sexy about it.
Also, the ending was given away early in the film. When defense attorney Matt Gavin (Chazz Palminteri) is nudging Corelli to work for his law firm, he knows Corelli won't let up until he gets his man. Gavin knows his long-time friend and sometime rival will find out the clues leads to him. It's better to have Corelli work for you than against you.