CrimeOnline’s Nancy Grace has weighed in following reports that accused killer Patrick Frazee’s mistress has not only pleaded guilty to tampering with evidence in Kelsey Berreth’s slaying but is expected to testify against him in his upcoming trial.

According to the Daily Mail, ex-nurse Krystal Lee Kenney, 32, tearfully confessed to tampering with evidence  — specifically  the Colorado mother’s cellphone  — during her first court appearance last week. She revealed that she was aware at the time that Frazee had killed Berreth, 29, days earlier.

Kenney is expected to be sentenced for one felony count of tampering with evidence after Frazee’s murder trial. The Daily Mail noted that she didn’t reveal exactly what she had done with Berreth’s cell phone, which pinged near a cell tower in Gooding, Idaho, the weekend following Thanksgiving, the last day that Berreth was seen alive.

Speaking with MailOnline, Nancy Grace said Kenney’s plea deal could make a big difference in Frazee’s trial.

“Krystal Lee Kenney’s conviction will have a huge impact on Patrick Frazee’s case because it’s now set that she will testify against him and she will be the State’s chief witness,” she said.

“Her testimony will be worth its weight in gold.”

Grace went on to note that the prosecutors aren’t without obstacles, as it’ll prove difficult to land a first-degree murder conviction without Berreth’s body. She speculated that police must have located evidence invisible to the “naked eye” in Berreth’s townhome which indicated a murder took place.

“I suspect they used luminol and found a vast amount of blood there,” Grace continued. “She’s dead and I think the jury will believe that.”

[Featured image: MailOnline video screengrab]