As I said in an earlier post this docu/drama is very close to home.
Given time constraints and artistic licence it was a decent representation of what happened and has been well received down this way.
Cooper was a bad guy, and from what I understand there are other unexplained deaths which he may be responsible for. I also believe the first murder enquiry could have nailed him.
He only lived a few hundred yards from the site of the first murders and drank with one of the victims in the 'Huntsman' pub.