The Golden State Killer may have been driven to rape and murder dozens of people because of an unending hatred for his ex-fiancee — a blogger who has gone into hiding, according to a report on Saturday.

During one of his sexual assaults, the fiend repeatedly screamed, “I hate you, Bonnie,” — a clue helped lead detectives to alleged killer James DeAngelo — who had a Bonnie in his past, an investigator told the The Mercury News.

Bonnie Ueltzen, the former Bonnie Jean Colwell, was engaged to DeAngelo in the early 1970s, but broke it off, and went on to marry a wealthy accountant, the Daily Mail reported

“Most certainly if he’s making the statement, ‘I hate you Bonnie,’ while he’s attacking another female, he is what we call a retaliatory rapist,” Paul Holes, a retired Contra Costa investigator who helped crack the case told the Mercury News.

“You’ve got to think Bonnie dumped him, he’s not happy about that, he still had feelings for her, who knows? But something along those lines must have happened,” he added.

DeAngelo met Bonnie Colwell when they were both students at Sierra College in Rocklin, California, 20 miles from Sacramento, the Mail reported.

The couple announced their engagement in the May 14, 1970 edition of Bonnie’s hometown newspaper, the Auburn Journal, which at the time wrote: “No definite date has been set for the wedding.”

DeAngelo, a graduate of Folsom High School and Sierra College, was employed by a crane and hoist company and affiliated with the Vet’s Club, honor society, President’s Honor Roll and the International Diving Association, the local paper said at the time.

Two years later, Colwell’s wedding to Michael Graf Ueltzen of Sacramento appeared in the Auburn Journal. More than 125 people attended the double ring ceremony on Aug. 12, 1972 at the Sunset Community Covenant Church in Rocklin. The newlyweds planned a honeymoon in the Spanish island of Majorca, the announcement said.

Ueltzen, 67, who currently resides in Sacramento, at one time lived near Assisi, Italy and wrote about her days there on her blog OldBroadAbroad. Ueltzen could not be reached for comment, and is in “hiding,” the Mail said.

DeAngelo, 72, a retiree and former cop from the Sacramento suburb of Citrus Heights, was busted last Tuesday. Police believe DeAngelo is responsible for at least 12 murders and 45 rapes over three decades, beginning in 1976.