| Martin Ennis |
|Behind the scenes|
|Portrayed by||Terry Kinney|
- "My father, as most of you probably know, hung himself in his garage a few months after the book came out. My mother never really got over it. She died less than a year later. You ask me, Kathryn, you all but put a gun to their heads."
- ―Martin Ennis to Kathryn Drummond [src]
Martin Ennis, known in some versions as Howard Ennis, is a serial killer who was pursued by Sherlock Holmes. He was studied and profiled by Kathryn Drummond, who published her own highly speculative and sensationalised analysis of him to great acclaim. In it, Drummond stated that Martin had been sexually abused as a child, claiming to have a reliable source. The fallout from this fabrication endangered several lives, including those of Holmes and Watson.