Patrick Frazee's nurse girlfriend, who helped him cover up the murder of his fiancee Kelsey Berreth, has been freed from prison after having her three year sentence reduced to 18 months.

Krystal Lee Kenney helped Frazee mop up his fiancee's blood and burn her body in a patch of ground on his family's Colorado ranch over Thanksgiving in 2018.

He beat Berreth to death after arguing about their break-up then called Krystal, who was a nurse in Idaho at the time, to help him 'clean up'.

She pleaded guilty to tampering with evidence in exchange for a plea deal and showed investigators where they had burned Kelsey's body.

On Tuesday, she was released from prison in Colorado. She is now expected to be going to a halfway house for a year of supervised living.

Kenney had argued that the judge went beyond her plea deal agreement by sentencing her to three years in prison instead of 18 months.

She won her case and had the sentence changed last month. She then got time served.

It's unclear exactly where in Colorado she is now.

Frazee was convicted of first degree murder and was sentenced to life without parole.

Over the weekend of Thanksgiving in 2018, he killed Kelsey then called Krystal - who lived 400 miles away - to come and help him clean it up.

It's unclear how Krystal and Patrick met. They dated on-and-off for years, including when he was with Kelsey.

Krystal told his trial that he'd confessed to killing Kelsey with a baseball bat at her home while their baby daughter was in a different room.

He then moved the body to his family ranch and disposed of it with Krystal.

They then pretended that Kelsey was missing.

Krystal was arrested before Patrick. She helped authorities unravel what he had done before he was taken into custody.

She apologized for her role in the murder, telling the judge: 'I know that saying sorry is not good enough.

'And I don't even know what the right word would be to describe the remorse that I feel.'