Could be a movie or made for tv. I recall watching it probably 30 years ago. Not a nice film but it's bugging me.
There's a deaf mute and blind guy (or combination of) who rapes or sexually assaults a woman. People think it's because he's had no sex education and is acting on instinct so they work with him to understand.
They think they've cracked it. He does it again.
Sound familiar?