Don't F**k With Cats: Hunting an Internet Killer was a pretty messed up show but really interesting. I had heard nothing about this true crime documentary, case, or Luka Magnotta prior to watching.
Without giving too much away, one day a video online is posted called 1 Boy 2 Kittens, and in this video a guy is seen with 2 kittens which he then suffocates in a vacuum sealed bag. This of course infuriates people and they form a online group on Facebook to try and see if they can find out who the guy is based on video evidence.
It seems the guy likes to taunt the group as he later posts equally as bad animal torture movies, and eventually it leads to him actually killing a person and posting that video. This is when the police are involved and a manhunt begins for Luka Magnotta.
The documentary is split over 3 episode all of which last around a hour long. I enjoyed watching it, thought though it's all a bit sickening, and you do see video clips in it such as him leaving a kitten out for a Python snake, and preparing a bathtub to drown a kitten, and even though you do not view the full clips, it's rather sad.