Getty/Netflix

Dramatizations of infamous serial killers use real pain to make a quick buck, and "Monster: The Ed Gein Story" is just the latest show to do it ... so says a prominent filmmaker with a connection to the series.

We spoke to Osgood Perkins -- son of the legendary actor and star of "Psycho," Anthony Perkins -- about the new series ... because his dad plays a prominent role in at least one episode. Getty

If you haven't seen the show, or know about the story, then spoiler alert ... Ed Gein's a vicious real-life killer and necrophiliac whom Robert Bloch -- the writer of the novel "Psycho" -- loosely based his main character, Norman Bates, on. Perkins played the character in the Alfred Hitchcock film classic.

The making of that movie is touched on in the second epis

See Full Page