A Colorado man accused of killing his fiancee will stand trial on murder and other charges -- including tampering with a deceased body -- later this year, a county judge ruled following a preliminary hearing Tuesday.

Patrick Frazee, 32, is scheduled to be arraigned in the death of 29-year-old Kelsey Berreth on April 8. He has been held in jail since his arrest in late December. Berreth, who had a 1-year-old daughter with Frazee, was last seen alive on Thanksgiving Day, and her body has not yet been found.

Testimony during the daylong hearing centered on what Frazee's paramour, 32-year-old Krystal Jean Lee Kenney, told investigators during their probe into Frazee's disappearance. Colorado Bureau of Investigation Agent Gregg Slater testified that Kenney told police Frazee characterized Berreth as an alcoholic who had physically abused the couple's daughter, Kaylee. Slater said there was no evidence that was the case.

Slater testified that Frazee began trying to convince Kenney to kill Berreth in September of last year. Kenney told police Frazee suggested a number of methods to kill Berreth, including poisoning her coffee and beating her with a metal pipe or baseball bat. According to Slater, Kenney said she failed to follow through with Frazee's instructions, leading him to say at one point at the end of October: "I guess if you can't do it, I'm going to have to."

Kelsey Berreth, 29, was last seen alive on Thanksgiving Day. (Woodland Park Police Department)

Slater also testified that Kenney told police that Frazee called her at her Idaho home on Thanksgiving Day and told her: "You need to get back out here right now, you've got a mess to clean up." When Kenney arrived at Berreth's townhouse in Woodland Park, Colorado two days later, she found a "horrific" scene with blood spattered on the walls and floors of Berreth's townhome, Slater said.

Kenney told police that Frazee convinced Berreth to wrap a sweater around her head and guess the scent of various candles then beat her to death with a baseball bat and stashed her body on a ranch. After she cleaned the house, Kenney said she went with Frazee to retrieve Berreth's body and watched as Frazee burned it along with the baseball bat on his property, Slater said.

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

Krystal Jean Lee Kenney has admitted to tampering with evidence. (Colorado Springs Police Department via AP)

Kenney took Berreth's phone to Idaho, where she sent text messages to Frazee and Berreth's employer posing as the dead woman then burned the phone, Slater said.

Kenney told police she wanted to please Frazee and feared that he would harm her or her family if she did not cooperate, Slater said. She has since pleaded guilty to tampering with evidence and is required to testify against Frazee as part of her plea agreement with prosecutors.

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The testimony did not reveal prosecutors' theory for a motive for why Frazee would kill Berreth. Her parents argue in a wrongful death lawsuit that they believe Frazee wanted full custody of the couple's 1-year-old daughter. The child has remained with them while the criminal case proceeds.

Investigators initially said Berreth was last seen on surveillance video with the couple's daughter at a grocery store near her home. However, police later found footage on a neighbor's surveillance camera showing Berreth, Frazee and their daughter at the entrance of Berreth's townhome later that afternoon.

Fox News' Kelly Burke and The Associated Press contributed to this report.