From the early 1980s, but still a fairly good science-horror story, I hope.

A Sherlock Holmes inspired, detective story.

John Forsyth was a police detective, with 18 years on the force. His only regret over all that time was that he was unable to save his first partner and best friend’s life, when they were pursuing a cult leader and serial killer. His only consolation was that he managed to put the nutcase away for life.