After months of mostly silence from authorities investigating the disappearance of a Colorado mother on Thanksgiving Day, grim details about her suspected demise emerged this week, including accusations that the woman's fiance beat her to death with a baseball bat while their baby was in the next room.

Testimony from investigators at a court hearing Tuesday also revealed that Patrick Frazee had repeatedly asked an Idaho woman with whom he was having an affair to kill Kelsey Berreth, the mother of Frazee's 1-year-old daughter.

When she refused, he did it himself, authorities said.

Berreth's body has yet to be found, but Colorado Bureau of Investigation Agent Gregg Slater said information he gleaned from Frazee's girlfriend, Krystal Jean Lee Kenney, indicates she watched as Frazee burned the woman's remains. Kenney is now cooperating with investigators after pleading guilty to evidence tampering.

Berreth, a 29-year-old flight instructor, was last seen on Nov. 22 near her home in a mountain town near Colorado Springs, south of Denver.

Investigators testified that Frazee began planning Berreth's death in September and enlisted Kenney. Court records released Wednesday show that Kenney's ex-husband told investigators his ex-wife and Frazee dated during college and had a sexual relationship in 2016 and possibly 2017. A detective said Kenney revealed they rekindled an affair in March 2018.

Kenney, a 32-year-old former nurse, told police that Frazee claimed Berreth was abusing the couple's daughter. Police said there is no evidence that the girl was abused by her mother or anyone else.

Frazee asked Kenney to kill Berreth three times, Slater testified Tuesday. He said Kenney reported that Frazee suggested poisoning Berreth's coffee in September. Kenney told police that Frazee later told her to hit Berreth in the head using a metal pipe and a baseball bat.

Kenney said he was angry each time she failed to act. She loved Frazee and wanted to make him happy but could not hurt Berreth, Slater said.

Kenney told at least two friends in October that Frazee had asked her to kill Berreth, according to the newly released court records. Both women were later interviewed by police investigating Berreth's disappearance but the records give no indication that they contacted law enforcement after Kenney's admission.

One woman, who works as a paralegal, told investigators she urged Kenney to contact police but "did not believe Krystal ever went," the records said.

Kenney received a call from Frazee on Nov. 22 demanding that she drive to Colorado, Slater said.

"You got a mess to clean up," Frazee said according to Kenney's account to police.

She said she arrived two days later and found a "horrific" scene with blood spattered on the walls and floors of Berreth's townhome, Slater said.

Kenney told police that Frazee had wrapped a sweater around Berreth's head so she could guess the smell of scented candles and then beat her with a bat and stashed her body on a ranch. According to court records, the couple's young daughter was present in the home but in another room at the time.

After she cleaned the house, Kenney said she went with Frazee to retrieve Berreth's body and watched as Frazee burned it on his property along with the wooden bat, Slater said.

She said Frazee later told her he planned to throw the remains in a dump or river.

Frazee was arrested last December, about a month after Berreth was last seen alive. Prosecutors announced additional charges this week, including tampering with a deceased body. He has not entered a plea to any of the allegations.

His attorneys focused most of their questions Tuesday on Kenney's account.

Police acknowledged that Kenney did not see Berreth's body or a baseball bat. They also said Kenney denied knowing Berreth or having a personal relationship with Frazee when investigators first contacted her in mid-December.

David Beller, a Denver attorney who focuses on criminal defense, said examining the motivations and credibility of a witness who is cooperating with prosecutors is an essential strategy for defense attorneys.

"The defense attorney is going to examine whether the witness is somehow minimizing her involvement or her motivations to make him look more culpable than he is," said Beller, who is not connected to Frazee's defense. "Juries are skeptical of a cooperating witness' testimony and a defense strategy is always to highlight that skepticism."

Frazee's attorneys also highlighted a lack of blood or other physical evidence detected in his truck and questioned the Berreth family's access to Kelsey's townhome following initial police searches. Blood in the bathroom identified as Berreth's was discovered Dec. 6, days after police turned the property over to her family.

According to court records, police found blood on a bottle of bleach and a mop during a mid-December search of Frazee's property. Tests are not complete yet.

The hearing did not reveal why prosecutors believe Frazee killed Berreth. Her parents argue in a wrongful death lawsuit that they believe Frazee wanted full custody of the couple's daughter. The child has remained with them while the criminal case proceeds.