Cat. III film is pretty much a direct ripoff of Danny Lee's Dr. Lamb. It opens with the arrest of a demented man who is accused of killing 14 prostitutes and the entire story is told through a flashback from our sicko killer.
Most would argue it but I personally prefer Diary Of A Serial Killer over Dr. Lamb. I feel there is more going on plot-wise and the movie never seems to slow down or bore. Dr. Lamb may have been first but this exploitative duplicate uses the formula perfectly. We get strangulation, murder by hair pick, murder by chop stick, fire crackers are wedged between fingers and toes and dynamite is shoved into a vagina for a nasty, mean spirited explosion. We have an incredibly sleazy scene that shows Brother Bill masturbating to bondage porn. His wife brings out the vegetable oil and lends him a hand. As she wacks away with the greasy cooking oil their daughter comes out crying. Mother waits for Bills O.K. before tending to the child. She pours the dirty dick-oil from the palm of her hand back into the container to be used for a meal later on. Now that's what I call an efficient house wife. We get lots of rape on display, a collection of pubic hair (the Japs would be offended), some gun violence, some nasty kitchen knife stabbing, lots of blood and it all makes for one twisted fucking movie.
Fans of this movie should check out The Untold Story also known as The Bun Man which is amongst the best of Category III films.