I don't know if Washington state is the winner in the most serial killers game, but there's plenty that have come from there.
I've stood in the basement of the King County courthouse when Gary Ridgeway (Green River killer) was escorted out right past me. He was hard to see with all the beef & subguns around him, but he was there.
Such a sweet man! He killed so many women over the years he couldn't remember where he'd put them all. He'd have sex with them for two or three days after he'd killed them. When asked why, he said it was cheaper. Saved him money.
His wife, kids and co-workers at the Kenworth Truck plant never had a clue.
Think for yourself.