Deranged (1974)
Gap-filling, I got around to watching Deranged (1974), a fairly obscure but respectably rated (imdb score = 6.4) indie Canadian horror film from the same year as Tobe Hopper's Texas Chainsaw Massacre. Deranged was produced the very diversely successful Canadian indie auteur Bob Clark (Black Christmas, Murder by Decree, Porky's, A Christmas Story, etc.).
Deranged presents itself as a kind of restaged documentary (with a Walter Cronkite-figure walking around inside crucial scenes narrating what's happening for our benefit) about a thinly disguised Ed Gein figure called "Ezra Cobb" who lives in a snowbound Wisconsin small-town. I'm not an Ed Gein expert but from what I remember of the case, the details of Ezra Cobb's case in the film do track the sad, pathetic details from Ed Gein's case pretty closely. It's completely not fun at all. Cobb is obviously supremely disturbed but the townsfolk nonetheless actively try to think the best of him and to include him in things right up to the point at the end of the movie when they finally visit his farm and discover everything including female bodies hanging up like dressed out deer in the barn. I believe that this was the sequence of events around Gein's case breaking open.
Anyhow, Deranged is worth a look for Psycho fans because Gein's case is in the background of Norman Bates' story, and with Deranged we get to see all the stuff that Psycho leaves to our imagination. E.g., we get to see Cobb's horrific mother, we get to see Cobb be present at her death, bury her, fantazise that she's still talking to him, dig her up after a year, progress through digging up more recently dead bodies to killing new victims all to get spare parts and company for a restored Mama. And so on.
The version I watched, which is on youtube in high quality (albeit w. spanish subtitles):
https://www.youtube.com/watch?v=INlk-M9LNoc
is an MGM blu-ray version from a few years ago that omits about a minute of the grossest body evisceration and restoration. The latest blu-ray edition from Arrow reinserts all that stuff. See here:
http://www.dvdbeaver.com/film4/blu-ray_reviews_59/deranged_blu-ray.htm
for details. Having watched the gross, additional stuff separately on youtube, I think I can say that it doesn't add much, and that the slightly censored MGM edition is fine for most people.