Officials convicted the longtime UC Berkeley employee that allegedly attacked and sexually assaulted nine women across six Northern California counties in 15 years dubbed as the “NorCal Rapist” on Wednesday for 46 counts of sexual assault and kidnapping.

Not more than a day after deliberation by the jury began, authorities convicted 60-year-old Roy Charles Waller in Sacramento County Superior Court. Not more than a day after the jury began its deliberation, authorities officially ended the four-week-long trial.

Authorities arrested the Benicia resident in September in Berkeley while he was working at UC Berkeley’s Environmental, Health & Safety office.

Prosecutors said Waller’s crimes began in 1991 after he sneaked inside a locked door and raped the woman living inside her Rohnert Park townhome. In 1992, he attacked a woman in Vallejo, and another on Halloween 1996 in Martinez. He hid his identity with a skeleton mask during the assault and later called to apologize to his victim.

Authorities said that he committed his other crimes in Woodland and Davis in Yolo County, while others were conducted in Chico in Blue County and Sacramento. Officials placed Waller on trial in Sacramento because it was the location of his last two rapes.

During the trial, the suspect denied involvement with the crimes but prosecutors had secured DNA evidence that linked him to the cases. 

According to authorities, the NorCal Rapist had blindfolded and bound his victims using duct tape. He would also brandish a gun or tell his victims that he was armed. Waller would frequently apologize or chat with his victims. In some cases, it was said that he would call them to apologize for using their ATM cards. 

“Nine victims waited for more than 20 years for this moment and it is only with the use of investigative genetic genealogy and the science of DNA that it has come,” Chief Deputy District Attorney Steve Grippi said. 

Joseph Farina, Roy Waller’s attorney, said the DNA evidence made the fight difficult. She also said the NorCal rapist could be convicted with a life sentence. 

“It was a DNA case — all about the DNA. There wasn’t much I could do about it. I could point out inconsistencies in the case, but in the end, it all came down to DNA,” Farina said. 

Waller is scheduled for his sentencing on December 18.