There was a chute in the middle of the building that went from the top down to the basement, where he had a massive oven built. No one knows how many actual victims died in that building.
Holmes was eventually caught and executed. Ironically, I think it was the insurance companies that Holmes originally cheated that helped track him down. I'm not a fan of capital punishment, but it's hard for me to argue against it in cases like these.
I hope Hell suits you well, H H.
There's a fantastic book by comic book artist Rick Geary that totally explains this case. You can Amazon.com Rick, who I don't know personally but admire his artwork tremendously, and Beast of Chicago, and his book will come up.
Just watch the Andy Griffith show before you go to bed and you'll be fine.