The other day as I was researching a murderer for Wicked Wednesday, I stumbled across a website I'd never seen before:
Murderpedia - The Encyclopedia of Murderers
From the site: "Murderpedia is a free online encyclopedic dictionary of murderers and the largest database about serial killers and mass murderers around the world."
Looks like it separates killers by gender and then either alphabetically by last name or by country. And when you scroll down to the United States, it has them by state. Pretty cool stuff - if you're into that (which I am).
BTW, not everyone in there is a mass murderer or serial killer. Some of its just single homicides. Still, a neat resource for writers and true crime buffs alike.