Produced by Susan Mallie, Lourdes Aguiar, Gayane Keshishyan Mendez and Lauren Clark

“She blogged about unsolved murders and missing persons. She was a beautiful writer,” true-crime journalist Billy Jensen says of Michelle McNamara.

But there was one case that consumed her. McNamara was obsessed with a prolific criminal who, for a decade, forged a path of destruction across the state of California — committing 50 rapes and 12 murders before he vanished. She dubbed the suspect “The Golden State Killer.”

“He was the boogeyman,” says Sacramento County District Attorney Anne Marie Schubert. “He was the man in the bushes that we didn’t know who he was and we didn’t know when he was going to strike again.”

McNamara was hot on his trail and was writing a book about him.

“She was really tired.  She had been pretty much awake for about three days.  I think she’d gotten, like, two hours sleep because there was a lot of new developments going on with the case,” McNamara’s husband, comedian Patton Oswalt tells CBS News correspondent Tracy Smith, talking for the first time about Michelle’s quest to find the elusive criminal.

“She thought she was getting real close to finding him.  And then she was gone,” Jensen says of McNamara’s unexpected death last April.

“What’s fascinating to me about this case is that it’s rich with so many clues. And frankly, it should be solved” – Michelle McNamara

Now … the race is on to find him.

 “The Golden State Killer was the most prolific serial predator in the nation.  He attacked across the state from Sacramento down to Orange County across 15 jurisdictions,” says  Contra Costa County cold case investigator Paul Holes.

Contra Costa District Attorney’s Office

Patton Oswalt is a comedian and actor known to millions of fans. Yet he would tell you it was his wife, Michelle McNamara, who was the true star of the family — something Oswalt sensed as soon as they began dating.

Patton Oswalt: I’ve met someone who is so much– so above my punching class in terms of intelligence and wisdom and empathy. …I was done for. She took a little bit of convincing.

But convince her he did in 2005.

Patton Oswalt: It was just like, “Oh, this is amazing.”

Tracy Smith: Is that how you felt, like you married up?

Patton Oswalt: Oh my God. …Like basically having a false passport that gets me into, you know, these amazing countries. …That’s the level that I married on with her.

Oswalt learned his new bride had some unique interests.

Patton Oswalt: You know, Michelle was always a writer. She had … published short stories and– and poetry. And … she was also always just fascinated with people – and — and just the messiness of a life.