An Idaho nurse who says Patrick Frazee admitted to killing his fiancée last year took the stand at his trial on Wednesday, testifying about their years-long love affair that ended with her cleaning up a murder scene.

Krystal Lee, an Idaho nurse and the government’s star witness, broke down in tears several times as she told a packed Teller County courtroom about her on-again, off-again relationship with Frazee—which began as an affair several years ago while she was married and included a secret abortion.

The relationship took an unexpectedly twisted turn last year, she said, when the 33-year-old cattle rancher asked her to kill his fiancée, 29-year-old Kelsey Berreth, with whom he had a 1-year-old daughter.

“I didn’t know what to do so I didn’t make correct decisions,” Lee said Wednesday, according to Fox 31. “He wanted her to not be a problem anymore.”

Frazee has pleaded not guilty to several charges, including first-degree murder, in connection with the disappearance of Berreth, who was last seen publicly in a grocery store with their daughter on Thanksgiving Day 2018.

Prosecutors allege that after Lee refused to help Frazee carry out various schemes to murder Berreth, the “cold, calculating manipulator” took matters into his own hands and fatally beat his fiancée to death with a baseball bat on Nov. 22, 2018. Frazee then allegedly buried his would-be wife’s body and the murder weapon—which have yet to be found—at his family’s ranch.

Lee, who pleaded guilty in February to evidence tampering, testified on Wednesday as part of her plea agreement. While Lee has denied participating in Berreth’s murder, she told jurors she helped Frazee clean up the crime scene and witnessed him burn the evidence of his crime.

Dressed in a sweater with a collared shirt, Lee recounted how they first met in 2006 at Colorado’s Teller County Fair while she was out with some friends.

“He was tall and handsome and we danced and seemed from the conversation that we had he was pretty admirable, and had his act together and seemed like a pretty good dude,” Lee testified, according to The Denver Post. She said they dated for a while but eventually broke up a year later because of the distance.

The nurse said the two kept in contact despite the break up and her new boyfriend, Chad Lee. On the day of her 2010 wedding, Frazee allegedly left her a voicemail pleading with her not to get married—and to be with him instead. Lee said she ultimately chose Chad because he was “a really nice guy” and she knew “he would be a really good dad.”

“But I felt like my heart was in love with Patrick,” she said through tears, while Frazee reportedly looked straight down at the defense table.

Lee said she didn’t try to reconnect with Frazee until 2015—when she and her husband hit a “rough patch.” Lee testified she drove to Colorado under the guise of visiting family and arranged a meeting with her former lover.

“It was like nothing had changed—it was still the same giddy feeling,” Lee recounted in court Wednesday, according to The Colorado Springs Gazette.

But in March 2016, Lee said their reignited love affair was tested after she became pregnant with Frazee’s child.

“He said ‘I guess you’re a baby killer or you’re not,’” Lee said, adding that she eventually had an abortion but told Frazee it was a miscarriage.

Lee said she filed for divorce from her husband two months later, but did not talk to Frazee again until October 2017. The nurse said that Frazee never mentioned his relationship with Berreth, or their child, until June 2018.

“My jaw just about hit the floor,” Lee told jurors, describing the moment she learned from a former boss about Frazee’s other relationship, according to The Colorado Springs Gazette.

Lee testified on Wednesday that she didn’t know what to do when Frazee asked her to murder his fiancée three times, claiming Berreth abused their toddler and he needed her help.

While she initially agreed, Lee said she later grew suspicious and backed out before every murder attempt—but never went to the police because she hoped “it would just go away.”

“His little girl is being abused,” Lee testified. “I understand if it was wrong. I didn’t know what to do so I didn’t make correct decisions.”

She described on Wednesday several schemes the cattle rancher came up with, alleging that he told her to kill Berreth with a Starbucks caramel macchiato laced with ambien and valium, a metal pipe, and a baseball bat.

“He grabbed a pipe and told me to take care of the problem,” she said at one point, according to Fox31.

Each time, Lee said she went to Berreth’s house with the intent of going through with the murder in case Frazee was watching, according to The Denver Post.

On Nov. 22, Frazee allegedly called Lee and said: “I need your help, and I need your help now. You have a mess to clean up.”

The nurse told jurors Frazee did not go into detail about what he meant until she was already in the car heading to Colorado. Later, he admitted he had killed his Berreth with a baseball bat after telling her to put on a blindfold for a “candle smell test.”

As Lee described in court how Frazee told her to “get the candles wiped up, get the bathroom done, and wipe up the footprints” during their frantic cleanup of Berreth’s apartment, the cattle rancher reportedly kept his head down and took notes.

Lee also testified that Frazee at one point threatened her if she failed to do a sufficient cleaning job.

“He asked me if I got it done. I told him the best that I could do. He said ‘You better hope you did, because your life depends on it,’” she said, according to The Gazette.

According to her, Frazee also revealed to her Berreth's last words: “Please stop.”

Frazee’s defense lawyers have dismissed Lee’s claims, alleging that she actually murdered Berreth and then “lied” to authorities to cover her tracks.

“What you have not heard is the raw and unedited version,” Ashley Porter, a defense attorney, said in her opening statements. “It looks good from the outside. It looks like it’s all there. But when you really start hearing the evidence and hearing the facts, you are going to realize deep foundational issues with this case.”

Berreth, a flight instructor at Doss Aviation, was last seen at a Safeway grocery store near her Woodland Park, Colo., home on Nov. 22, 2018. Ten days later, Berreth’s mother, Cheryl, reported her missing to authorities when she grew concerned after not hearing from her daughter for ten days.

Frazee told authorities at the time that he last saw Berreth on Thanksgiving Day, when she dropped off their daughter, Kaylee, at his home. But photos from Berreth’s neighbor’s surveillance camera show Frazee at his fiancée’s front door 11 times that day, according to witness testimony and images displayed in court Tuesday.

One image shows Frazee outside Berreth’s house at around 4 p.m., before he showed up late to Thanksgiving dinner at his family’s house about an hour later, his brother Sean testified in court.

According to his brother, Frazee brought the couple’s daughter with him and made up an excuse for his fiancée’s absence. “He explained to me that her grandmother was sick and that she may have been visiting her sick grandmother,” Sean Frazee said.

Woodland Park Police Cpl. Dena Currin testified on Monday, saying Frazee never seemed concerned about the investigation and even told authorities the pair had broken up days before she went missing—prompting suspicion.

Prosecutors played a Dec. 2 phone call between Currin and Frazee, in which the 33-year-old said the last time he had spoken to Berreth was when she dumped him. “We basically had a heart to heart that this wasn’t working out, that she wanted to go our separate ways,” Frazee told Currin.

Frazee, who lived on a 35-acre ranch with his mother, was arrested and charged with his fiancée’s murder on Dec. 21.