"Two hours of writing fiction leaves this writer completely drained. For those two hours he has been in a different place with completely different people." - Roald Dahl
With a few exceptions, I've avoided writing (or reading, or seeing films) about serial killers, child molesters, and murderers, mostly because these are not people I want to spend time with.
If you do enjoy vicariously confronting horrible people, perhaps making sure they get their comeuppance more often than is the case with their real-life counterparts, that's great, too.
Either way, I hope you're taking advantage of our unique ability as writers to create worlds and people to live within and to share with thousands or even millions of our fellow escapees.