ABC News January 28, 2020

Patrick Frazee's ex-girlfriend Krystal Lee gets 3 years in prison in Kelsey Berreth murder case

WATCH: Patrick Frazee accomplice sentenced to 3 years for her role in Kelsey Berreth murder

Krystal Lee, the ex-girlfriend of a man who murdered his fiancee, was sentenced to three years behind bars Tuesday -- the maximum sentence possible -- for helping dispose of evidence in the gruesome crime.

"I'm sorry that my silence was mistaken for lack of remorse or sympathy," Lee said in court Tuesday. "I'm sorry her family will live the rest of their life without her. I'm sorry Kaylee will live without a mother."

MORE: Patrick Frazee found guilty of killing missing fiancee Kelsey Berreth; sentenced to life without parole

"I'm sorry that I did not save Kelsey," she said.

Woodland Park Police Department
Kelsey Berreth is pictured in an undated handout photo.

Lee's sentence is in connection to the crimes of her ex-boyfriend Patrick Frazee, who was found guilty of killing his missing fiancee, Kelsey Berreth, in November. He was sentenced to life without parole plus 156 years.

Teller County Sheriff via KMGH
Patrick Frazee, the fiance of missing Colorado mother Kelsey Berreth, is pictured in a booking photo released on Dec. 21, 2018.

The star witness against Frazee during his dramatic trial was Lee -- his ex-girlfriend with whom he later had an affair -- who told the jury that Frazee called her to come to Berreth's Colorado house to clean up the crime scene.

Lee testified that Frazee beat the mother of his child to death with a baseball bat on Thanksgiving Day 2018 while the couple's 1-year-old daughter, Kaylee, sat in a back room.

MORE: Kelsey Berreth murder trial: Patrick Frazee had hit list of witnesses to kill, inmate says in testimony

"I saw blood all over the floor and blood all over the wall... on the floor there were bloody footprints," she testified.

Lee admitted to disposing of Berreth's phone and pleaded guilty to tampering with physical evidence.

Jerilee Bennett/The Gazette via AP
Krystal Lee is lead to a van by representatives of the Teller County Sheriff's Dept. after being sentenced at the Teller County Courthouse in Cripple Creek, Colo., on Jan. 28, 2020.

Lee also claimed that Frazee had three prior plots for killing Berreth, including one that involved Frazee asking her to poison Berreth's favorite Starbucks drink, a caramel macchiato, according to investigators. Lee claimed she and Frazee discussed potential drugs that were easy to access because Lee was a nurse, an investigator said.

With over a dozen of Lee's family and friends in the courtroom Tuesday, a witness on her behalf testified that Lee was not a killer and was also a victim of Frazee.

But in court in November, Berreth's mother, Cheryl Berreth, called Lee "an active participant in the murder -- the only thing she didn't do was swing the bat."

MORE: Patrick Frazee's mistress offers gory testimony during Kelsey Berreth murder trial

"Kaylee's mommy would still be alive if Krystal would have gone to the authorities. As a nurse ethics require her to do no harm," Cheryl Berreth said.

"She chose to cover up the murder, only speaking out to save herself. She chose to clean up the mess," Cheryl Berreth said. "We have seen no remorse for anything other than getting caught."

Kelsey Berreth's body was never found.