White, Hairy Creature Haunts Castle in 80's Film

by Jason
(Waynesboro, Pennsylvania, USA)

I vaguely remember parts to a movie I saw in the mid 80's set in a castle or huge mansion where people are murdered violently by a white, hairy creature or demon.

One person is killed by something resembling a meat hook and another (a detective or cop) is pulled down into the ground in front of a tombstone in the front yard, but is able to get back out quickly.

Does anyone remember the name of this film?