For decades, Bonnie Ueltzen kept quiet about the teenage romance that nearly ended with her walking down the aisle.

She had been engaged to Joseph DeAngelo, the man who would go on to become the Golden State Killer, but ended the relationship and gave back the ring. Soon after, he turned up outside her family’s home in the dead of night with a gun.

Now, in her first media interview, Ueltzen is breaking her silence about the terrifying encounter, speaking exclusively for Fox Nation’s new four-part documentary, The Golden State Killer: Unmasking A Monster.

‘I was absolutely in a panic,’ she said. ‘I had no idea if he would pull the trigger.’

Ueltzen said she regrets never reporting DeAngelo to police, particularly because the encounter came shortly before he is believed to have embarked on the crime spree that would terrorize California for years.

DeAngelo, now 80, was eventually linked to a lengthy string of sexual assaults and murders across the state. During his crimes, he reportedly told at least one of his victims: ‘I hate you, Bonnie.’

‘I wish things had gone differently. I wish as a 19-year-old I had stepped forward, taken the initiative, talked about it,’ Ueltzen said in the new series.

‘I wish that my father had picked up the phone, even after the fact, and reported it,’ she added. ‘It may just have put him on another track. No one will know.’

Detectives uncover the identity of ‘Bonnie’

The revelations come more than six years after DeAngelo admitted to a staggering 161 uncharged crimes, on top of pleading guilty to 13 murders and 13 kidnappings, many of the crimes being sexual assault that were too old to prosecute.

But what drove DeAngelo to unleash his decades-long reign of terror remained largely a mystery.

For years, investigators quietly wondered whether the answer could lie with a woman named Bonnie – a name one of his victims remembered hearing DeAngelo say as he sexually assaulted her in 1978.

‘As the East Area Predator is physically sexually assaulting the victim, he is sobbing and saying, “I hate you, Bonnie. I hate you Bonnie,’ over and over, investigator Paul Holes told ABC News’ 20/20 in 2018.

‘That told me he had some significant female in his life named Bonnie. He had some anger against what Bonnie, or what he perceived Bonnie, had done to him. And he’s taking that anger out on this victim that he’s sexually assaulting,’ he added.

‘We didn’t know, was Bonnie his mom? A wife? Ex-wife? Girlfriend? We just knew that there was a Bonnie in his life.’

The breakthrough came when detectives unearthed a newspaper article announcing the engagement of Ueltzen, then Bonnie Jean Colwell, to Joseph James DeAngelo – finally giving a face to the mysterious Bonnie.

Bonnie recalls DeAngelo’s anger

‘Now we have a guy that has a Bonnie in his life, and we couldn’t find any indication that they ever got married,’ officer Holes explained in the 2018 segment.

‘So, something happened in that relationship that caused them to part – and that probably is indicative of a relationship that went sideways,’ he added.

The mystery of what happened between the pair – and whether it played any role in setting DeAngelo on his path toward barbaric violence – is finally explored in the new documentary.

According to Ueltzen, it all began with an argument over school.

The pair had started dating at just 18 and were in their first semester at California State University when they enrolled in what she described as an ‘abnormal psychology’ class.

Ueltzen was pulling straight A’s while DeAngelo was failing – a disparity she said soon became a source of bitter conflict, with his behavior growing increasingly ‘aggressive and angry.’

She said he demanded that she help him cheat on the next midterm exam so he could secure a passing grade, but Ueltzen, the daughter of two teachers, said cheating was simply a boundary she would not cross.

‘It was the only thing he wanted to talk about,’ she said. ‘The rest of our life went on hold while he was trying to get me to comply with what he had planned and I was having none of it.’

The constant tension eventually reached a boiling point. Ueltzen, who had become engaged to DeAngelo shortly after they began dating, said she realized she ‘did not want to spend more time with this man.’

Bonnie recalls DeAngelo’s gunpoint demand

At 19, she made the decision to call off the engagement.

She invited DeAngelo to her parents’ home, where she broke the news and returned his engagement ring. She said he left ‘very, very angry’ – but what happened next would haunt her for decades.

Two weeks later, Ueltzen was asleep in her ground-floor bedroom at her parents’ home when she was jolted awake by a tapping sound coming from the glass window.

‘It was Joe standing outside and he had a revolver in his hand and he was pointing at me through the window,’ she revealed.

He ordered her to get dressed, telling her they were going to Reno, Nevada, that very night to get married.

Ueltzen said she managed to slip out of bed and wake her father, who took DeAngelo outside to the front porch, where the two talked for what she estimated was nearly two hours.

DeAngelo eventually left, and law enforcement was never called. It would be the last time Ueltzen saw him for nearly five decades – until his arrest in 2018.

‘I have no idea what that conversation was about,’ she said. ‘To the day that he died, he never discussed it with me.’

Bonnie recalls disturbing incidents with DeAngelo

Ueltzen has her own theory about what happened on that night: she believes her father struck a deal with DeAngelo – no call to police in exchange for never contacting her again.

‘And he never did,’ she said during the interview.

During their few months together, however, Ueltzen recalled several disturbing incidents, including one in which DeAngelo killed a dog while the pair were riding his motorcycle.

She said a German Shepherd would regularly chase them as they rode, and one day, when the dog approached, DeAngelo ‘turned and kicked it underneath the chin.’

‘The dog dropped dead,’ she said. ‘I think it broke its neck.’

She also recalled DeAngelo introducing her to firearms, even buying her a .22 rifle. The couple would practice target shooting together at his home.

‘He liked guns,’ she said. ‘He was very proficient, and he would get into restricted property where he would go poaching for fish and game.’

DeAngelo’s volatile marriage and secret crimes

The couple never married. Instead, DeAngelo went on to marry Sharon Huddle in 1973, and they eventually had three children before separating sometime in the 1990s.

But behind closed doors, neighbors later described the marriage as troubled and volatile.

‘He would come by on a regular basis and scream and yell from the driveway and never step inside,’ one neighbor, who asked to remain anonymous, told the VC Star in 2018.

‘He and Sharon would get in epic shouting battles. It was a very volatile relationship when he came over, and it was not good,’ they added. ‘It was just very toxic.’

Meanwhile, DeAngelo, a former police officer, spent four decades hiding in plain sight as he terrorized California under a succession of names – the Visalia Ransacker, the East Area Predator and, ultimately, the Golden State Killer.

He evaded law enforcement for decades until investigators turned to a revolutionary DNA technique that finally exposed him.

DNA breakthrough led to DeAngelo’s capture

His genetic profile was linked to the crimes through GEDmatch.com after a relative had uploaded their DNA to the genealogy website, helping detectives trace the connection back to him.

In April 2018, a 72-year-old DeAngelo was arrested at his Citrus Heights home, where he reportedly protested in a high-pitched voice: ‘I have a roast in the oven!’

When Ueltzen learned from her husband that DeAngelo had finally been arrested, she said she was ‘absolutely floored.’

Prosecutors had initially sought the death penalty, but DeAngelo struck a plea deal in which he agreed to plead guilty to all charges in exchange for life in prison.

In August 2020, DeAngelo was sentenced to 11 consecutive life terms without the possibility of parole, plus eight years, bringing an official end to his sinister decades-long saga of kidnappings, sexual assaults and murders.

‘It’s difficult to carry for me that I was ever involved with him,’ Ueltzen tearfully said in the new documentary. ‘That he is the cause of so much damage to people, to other women, to the people that he murdered in the most brutal, brutal ways.’