SACRAMENTO (CBS SF) — A Benicia man has been arrested for being so-called NorCal Rapist, who terrorized victims from the Bay Area to Sacramento over a 15-year period beginning in 1991.

Sacramento District Attorney Anne Marie Schubert and Sacramento Police Chief Daniel Hahn made the announcement at a Friday morning news conference that 58-year-old Roy Charles Waller was in custody.

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Schubert said Waller has been charged in Sacramento County with 12 counts of forcible sexual assault against two women with allegations he used a gun and enhancements which if he is convicted will carry a life sentence.

Law enforcement has also linked Waller to at least eight other sexual assaults in six Northern California counties.

Hahn said he had been arrested by Sacramento deputies on Thursday as he arrived for work at the University of California, Berkeley, where he has been employed in the Environment, Health & Safety office since 1992.

His on campus duties included: “managing programs to help ensure safety and training regarding the use of equipment and machinery including forklifts, aerial lifts, respirators, etc.”

“The answer has always been in the DNA,” Schubert told reporters. “For 27 years the individual who came to be known as the NorCal Rapist victimized at least 10 women across Northern California.”

The DNA match in the case was made through the genealogy website that was used to catch the Golden State Killer.

“The link was made through genetic genealogy,” Schubert said. “Through the use of GEDMatch.”

She said the match had come to light just in the last 10 days.

“The genealogy was done approximately 10 days ago,” the Sacramento DA said. “Which led us very quickly to this individual and within the last 10 days the police department has undertaken a massive investigation which culminated yesterday with his arrest.”

Neighbors said that Waller lived with his wife and was, like his home, quiet and unassuming.

“Those people that you least expect…sometimes you never know,” said neighbor Marsha Shigemotto. “From a distance he seemed normal. I mean, he was cutting down the trees and pruning and they were laughing, I think.”

UC Berkeley officials issued a statement saying they were shocked by the arrest.

“We were shocked today to learn that a campus employee was arrested in connection with a series of rapes that occurred more than a decade ago in several Northern California communities,” the statement read. “The employee, Roy Waller, was taken into custody by police and is on investigative leave.

“According to UCPD and the Sacramento Police Department there is no indication that any crimes occurred within the campus community, however UCPD will be reviewing any open sexual assault cases to determine if any might be related. UCPD continues to work in cooperation with Sacramento police.”

Benicia police said Friday investigators were looking into whether Waller could be a suspect in any cases where he lived.

Investigators believe the NorCal Rapist reign of terror began with an assault of a woman in her Rohnert Park townhouse in 1991 and then continued as far south as Vallejo in 1992 and Martinez in 1996.

Martinez police said the suspect wore a skeleton mask and attacked a woman in Martinez on Halloween and then called her at work less than three weeks afterward to apologize.

In the Central Valley, the rapist has been linked with attacks as far north as Chico and as far south as Sacramento, Davis and Woodland.

Authorities say the NorCal Rapist targeted petite Asian women in their 20s and 30s. He was armed in many of the assaults and often wore a mask.

Waller is due to make his first court appearance in Sacramento on Monday.