The Ann Rule origin story is well known to true crime buffs, but since I’m not sure how many of those read this blog, I’ll recap it here: in the 1970’s, she was working at a suicide hotline and writing under pseudonyms. She became interested in some Seattle area murders and started investigating them; ultimately, it turned out those murders were committed by a close friend who worked with her on the hotline…
…one Mr. Ted Bundy. The Stranger Beside Me made Rule’s reputation and career.
“I really care about the people I’m writing about,” said Rule, whose accounts focused as much on the anguish of the victims and their families as on the depravity of the killers. “I finally came to the knowledge I’m doing what I probably was meant to do in life.”
Edited to add: WP article which goes into more detail about Bundy and Rule.