The murder of Laci Peterson - a 27-year-old expectant mom - has been the subject of true crime for two decades since her husband Scott was found guilty of killing her.
But there was a third person involved in their marriage in 2002 - a woman who became a critical part of detectives' case against keen golfer and dad-to-be Scott.
Amber Frey, now 49, was unknowingly Scott's mistress for weeks before he killed his heavily-pregnant wife Laci - and she cunningly kept her relationship going while helping police nail Scott as the suspect in the chilling murder case.
Now, a trove of their intimate phone conversations have been made public.
Frey, who was a single mom to her young daughter at the time, revealed that she had just finished school in California when one of her friends told her that there was this 'handsome guy' who was looking to 'meet the one,' and introduced her to Scott.
Speaking on Netflix's new series 'American Murder: Laci Peterson,' Amber said of her blossoming new relationship with Scott: 'We started talking on the phone.
Amber Frey, now 49, has spoken out about her days as Scott's mistress in 2002
Scott Peterson and Amber Frey, pictured together at a holiday party on December 14, 2002
'I thought he was handsome, he had a really nice smile, he had a good head on his shoulders. He was interested in my life and my daughter, and he was sweet with her.
'We laughed a lot, we had some good conversations.'
During their courtship, which she said started around November 2002, Amber asked Scott if he had ever been married - and he said no.
When she asked if he wanted kids in the future, Amber recalls that he said that her own daughter Ayiana 'would be enough.'
Amber, who now lives in Fresno, California, said: 'I asked if he'd ever been married, he said no. My feelings for him were growing and I could see myself potentially marrying him one day.'
She revealed that in the early days of dating, Scott would show up to her home with three dozen roses and was a real romantic - until his lies started to unfold.
Laci Peterson, aged 27, pictured on December 14, 2002 - on her own at a different holiday party, while her husband was miles away at a separate event with his mistress Amber Frey
Laci with her husband Scott - who killed her just weeks before welcoming their baby boy to the world. The couple met in 1994 at Cal Poly and dated for two years before moving in together
Amber said that on December 9, 2002, she got a worried phone call from Scott saying there was 'something he needed to tell her.'
She recalled that they were holding hands at the table in her home when he told her he 'lied about being married,' while choking up and crying.
But his unnerving lies continued.
Amber said: 'He said he had "lost" his wife and this would be the first holidays without her. I remember just comforting him.
'With all his emotions, I thought "I don't want to pry, he will share what he feels comfortable with."
'He was sorry he had lied to me and hoped that it hadn't changed anything.'
Amber, then 28, said that she continued on with their relationship, forgiving him for what she believed was just a white lie he told about not being married before.
In reality, when she told investigators this story, alarm bells rang out - because December 9, the day he told Amber he had 'lost his wife,' was the same day he bought the boat which he eventually used to dump Laci's body in the water.
It was only in late December when a friend sent her a newspaper snipping of missing Laci Peterson, and a description of her husband, that Amber put two and two together about Scott's 'lost wife.'
Recalling how she felt when she realized the man she'd been dating had been lying about having a wife, who was pregnant and now missing, Amber said: 'I was definitely in shock, I couldn't stop crying.
Amber had been introduced to Scott by a friend, and their relationship was great from the beginning - with the San Diego-born man buying her flowers and talking about their future
The couple - whose love story came crashing down when Amber realized he was complicit in his wife's disappearance and death - are pictured together in December 2002
'It was terrifying to think that the man I was getting to know had something to do with his wife's disappearance.
'I was in disbelief. Everything was a lie.'
She called the Modesto Police Department on December 30, 'eager to tell them everything she knew.'
When Amber went to police, she provided them with crucial evidence that led them to realize Scott was living a double life - pictures from their holiday party.
She showed cops pictures of herself and Scott, beaming while wearing a red dress and tuxedo, at a Christmas party on December 14 - which was the same day Scott's wife Laci attended another holiday get-together alone.
The picture of eight-months-pregnant Laci, wearing a maroon outfit and cradling her growing bump, was one of the last that her friends ever took of her before her death.
Unbeknownst to Laci, her cheating husband was miles away on the very same night, smiling and snuggling up with his mistress - whose ruby-red dress he matched to the color of the flower in his lapel for the festive celebrations.
An intimate photo of Scott and his mistress Amber - who did not know he was married
Amber and Scott snuggle up together at a holiday party in 2002 - all while his pregnant wife was at another party. Scott killed his wife and their unborn son days after this photo
Amber Frey, pictured with her young daughter Ayiana
Amber, pictured in November 2023
Amber told the docuseries that she immediately began cooperating with police - and promised to not tell Scott that she had spoken to them.
Under the direction of detectives, she started taping her phone calls with him - recording their intimate conversations and sending the evidence to police.
Scott, who was not aware that his girlfriend had cottoned on to his complicity in his wife's disappearance, continued as normal with Amber - chatting about their upcoming plans and calling often to tell her he missed her.
The Netflix show has unearthed these calls for the first time.
As the weeks rolled on and the Californian community frantically searched for missing Laci, Amber kept on collecting evidence from Scott, but she admitted: 'I found very little innocence in his behavior.'
She recalled that the ordeal of tapping her own phone made her heart 'never stop pounding' when she took Scott's calls.
Soon, the public grew more and more suspicious of Scott - and around the time that support for him started to wane, he decided to call Amber.
On January 6, 2003, he confessed over the phone: 'I've lied to you.
'[Laci] disappeared just before Christmas.'
Shocking audio of their call revealed how Amber confronted Scott and his web of lies - especially over the fact that he said he 'lost' his wife on December 9.
Scott could not give a straight answer.
He said on the phone: 'I said that I lost my wife. I did, yes.
'There are different kinds of loss, Amber.'
Pictured: The boat that Scott Peterson bought on December 9, 2002. This is the same vessel he used to take his dead wife's body out into the San Francisco bay. He bought it on the same day he told his mistress he 'lost' his wife
Prosecutors said Peterson killed Laci (pictured together) to escape married life and fatherhood
Scott Peterson appears in a California courtroom in February 2002
While tearing up, he said on the crackled call to Amber: 'Sweetie, you think I had something to do with her disappearance?'
'I am not evil like that.'
But word soon came out that Scott had a mistress around the time his wife disappeared - and Amber started getting hounded at work and home from journalists trying to get her to answer questions.
The ordeal led her to do a press conference of her own on January 23, 2003.
A taped phone call Scott made to Amber afterwards revealed that he thanked her for doing it, and said that he 'pulled over [his car] and threw up when you cried.'
It was soon after that Amber made the decision to cut all contact with Scott.
Pictured: Scott and Laci Peterson Scott Peterson on their wedding night
Peterson was initially sentenced to death before a judge overturned the decision in 2020 and sentenced him to life without parole
On April 13, 2003, the body of a full-term male infant washed up on the shoreline of the San Francisco Bay. Laci and Scott were going to name their son Conner.
One day later, the body of a recently pregnant woman washed up one mile away. The body was missing the head and arms. DNA testing confirmed it was Laci Peterson.
A pathologist confirmed that the fetus had died in utero.
Scott Peterson was arrested on April 18, 2003. He went to trial, and on November 12, 2004, the jury convicted him of two counts of murder.
The first was first-degree murder with special circumstances for killing Laci, and second-degree murder for killing the fetus she carried.
Scott was given a death sentence - but this was overturned in 2020, and he was re-sentenced to life in prison without the possibility of parole.
Peterson, who is also said to have dreaded becoming a father, maintains his innocence and claims Laci was killed after disturbing a burglary.
