*WARNING: SPOILER INFO*
The murder scene was filmed three times (Much to the dismay of Sheryl Lee!) to protect the secret of who killed Laura Palmer from leaking to the public.
It was shot once with Richard Beymer (Ben Horne) as the killer, then again with Ray Wise (Leland) and finally with Frank Silva (Killer BOB). David Lynch and Mark Frost had told Richard Beymer that he was NOT the real killer, and he has said in interviews he had a lot of trouble filiming the brutal murder sequence.