I remember a scene. I do not remember but I think it was near the beginning of the movie. I think this move came out in the 90’s . A guy is tied to a bed arms and legs, and a hot girl (who appears to be a prostitute) is giving the guy a massage, she is using some kind of massage oil. At some point she gets up and walks to a door that leads to the outside (I think) hallway. She lights a cigarette and at this point he realizes the massage oil was actually some kind of flammable liquid. I think lighter fluid. He start to scream or yell at her or something, maybe beg, then she take the cigarette and flicks it at him on the bed. He screams and she leaves and I think that is the scene best I can remember.
If I remember correctly it turns out the guy tied to the bed was a witness (maybe he was going to rat out the mob). The girl was sent there to assassinate him so he could not testify. I do not believe the girl is in the movie again and there is a guy and a girl detectives or cops that are the main characters of the movie.