Name of movie...?

[thx1139a]

Does anyone remember the name of a movie, late 70s, featuring a serial killer that breaks the fingers and limbs of his victims? There was one scene in particular in his van where he had lured a couple of hotties... one of which he ripped the front of her one-piece bathing suit off of (revealing a seriously perfect chest) before holding up her hand and pulling one of her fingers backward until is snapped as she stared at it, gagged and screaming. Wulf and I were discussing it but I couldn't remember the name.