Spoiler warning.
When the main character's sister is pushed down the stairs, the killer breaks a glass of vodka next to her, to make it appear that she's been drinking. But right before she is killed, tells her sister's business partner (Teri Garr) on the phone that she hasn't had a drink in 4 days. Yet the police never mention the results of a toxicology report! And, the characters talk about her being drunk when she fell down the stairs. Huh? Really bad mistake in this movie, which is pretty awful, overall.
Surprisingly bad, considering the great cast. Some faults: the writing isn't very good, the music is made-for-TV bad, and there is no tension at all because we already know the answer to the mystery from the first scene in the movie.

A young neurosurgeon inherits the castle of his grandfather, the famous Dr. Victor von Frankenstein. In the castle he finds a funny hunchback, a pretty lab assistant and the elderly housekeeper. Young Frankenstein believes that the work of his grandfather was delusional, but when he discovers the book where the mad doctor described his reanimation experiment, he suddenly changes his mind.