Why do serial murderers stop killing?

I think the Dennis Rader case may have forced behavioural scentists to re-think some of their previous assumptions on serial killers. Though I have relatively little faith in the FBI profilers and behavioural scientists. As for Jack the Ripper and Zodiacit is not known why they stopped. Or indeed if they did stop. Both may have died; imprisoned for a different crime; or, perhaps (less likely) they changed MO.

I’d like to think they caught the plague, got run over by a horse and carriage, or a taxi cab. A mundane twist to their life of murder/danger/excitement/intrigue.

Good point. Maybe the serial killer is doing 20-life for an armed robbery, but we don’t know it because we haven’t been able to link the murders to him yet. Or maybe he died in a car wreck. Maybe he gave up his killing ways and settled down to teach third grade in rural Tennessee. We just don’t know - because the killer was never identified, we can’t track what happened to him.

Have there been any serial killers identified a long time after the last known crime? Was any investigation done as to what they had done with their life in the intervening years (e.g. commit more crimes that were not reported, backpack around China, finish a degree at Florida State, whatever)?

Yes. Yes. Three examples are in post 55.

I don’t know how prevalent stopping without arrest is among serial killers though.

Apparently that hypothesis has been debunked. Casebook is the go-to website for Ripperology:

Intro page: Casebook: Jack the Ripper - Introduction to the Case
FAQ page: Casebook: Jack the Ripper - Frequently Asked Questions
From the FAQs, the debunking: Casebook: Jack the Ripper - Frequently Asked Questions

IANARipperologist: I’ve only read the intro and part of the FAQs.

an even creepier question is: isn’t it possible that there is a serial killer out there who has been killing for decades, but not with any particular method or pattern, so they just haven’t realized it!?

DUN DUN DUHHHHHH!!!