SACRAMENTO (CBS13) — They chased him for years, hiding out where he was known to strike, hoping one day they’d catch him.

Even though that never happened during the East Area Rapist’s crime spree, some local law enforcement who worked on this case say they’re deeply satisfied at what investigators were able to piece together decades later.

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One now-retired detective was watching every word as it unfolded Monday.

“So I always believed that he would either die in custody, waiting for trial or that he would take a plea deal,” retired sergeant John Cabrera said.

The plea deal came as no surprise to Cabrera. As an officer with the Sacramento Police department during the height of Joseph DeAngelo‘s sexual assault crime spree, he knows the case inside and out.

“I was working the patrol division in the special assignment division because Mr. DeAngelo was hitting my district,” he said. “We walked the river levees — no matter what weather — we were out there and we were deep into that neighborhood saturating it every night,” Cabrera said.

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Every night they’d come up empty, but the feelings this now-retired officer had back then were filled with worry.

“When I was investigating him and we were doing our assignments out on patrol, he was primarily doing sexual assaults, but we always talked about it would only be a matter of time,” he said.

Fast forward more than four decades, and the man they waited for in the cover of darkness has finally emerged. After going into hiding after so many years of causing pain, Cabrera has a theory on why DeAngelo stopped his crime spree in the late 80s.

“In 1986, DNA was now coming out and being used to identify suspects, in particular, in sexual assault cases,” Cabrera said.

Years later, it would be a different type of DNA gathering that DeAngelo could not escape. Even though the cases gathered dust, they stayed fresh in the minds of investigators like Cabrera, who got their man after all these years.

“Well, I’ll always remember this,” he said.

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DeAngelo’s victims will always remember the day justice was served. Cabrera also has a message for criminals out there who committed their crimes years ago and now think they got away with it: with advanced DNA technology, don’t be surprised, he says, to hear a knock on your door.