Ok, im just telling what i remember.
1) the movie starts with a woman who i think is the main actor’s wife. She disguises into another woman(i think she wears a wig not sure) and visit her husband at his office.
2) They are role playing sexual game i think and they have sex in the man’s office.
3) The couple (or only one of them, not sure) have a son. He’s like 6 or 7.
4) So then, one night the woman gets murdered by an Anonymous murderer on her bed i think.
5) the husband returns home and the police is already there and he discovers her death.
6) The son is the only witness but he cannot talk i think, so the police asks him to draw a picture of the killer( which is still not revealed in the end and the suspense is kept)
7)(not sure) I think that there was a killer which nearly got out of prison who was known to kill his woman victims by raping them and killing them on the bed and attaching them. But they discover the woman wasn’t raped.