My Father The Killer: Thriller

I waited until after my father died to announce to the press that he was the Swishline Killer, the one that they'd all thought must have been put in prison or died years ago. Nope. Not dead. Living out and enjoying his retirement in the Florida Keys, killing nothing more than fish and the occasional gator. I don't know if they believed me. There isn't really proof; we saw to that, mom and I. That was when he was still alive and it seemed like it mattered that nobody should ever know. I grew up, went off to college, came back home. I saw my dad a lot. When mom died, I was right there with him. He urged me to go off and get a job, but I saw the darkness in his eyes, and I knew that if I did--

Inspiration: News headline: "Californian Says Father Was Zodiac Killer" (http://www.nytimes.com/2009/04/30/us/30zodiac.html?ref=us)
Potential: Low.
Notes: Retired serial killer? I dunno. Seems...not very interesting. Maybe a short story, if there's a unique enough additional angle, but not anything longer.