I have been trying to remeber the actor...

It might have been Pacino...

A cop goes undercover as a gay guy to catch someone who has been murdering gays. He really gets into the character and it makes him feel very uncomfortable. Not one of my favorites and if I recognize the name of the movie I will never watch it again. Very low budget type of movie. The pants were damn tight though. Might even have had a couple of holes in the seat too.