Search warrants have been served in Twin Falls, Idaho, in relation to the case, a Twin Falls Sheriff's Office spokeswoman said.
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A 32-year-old nurse there is suspected of disposing of Berreth's phone, a law enforcement official told NBC News. Berreth's phone last pinged on Nov. 25 near Gooding, Idaho, which is less than 40 miles from Twin Falls, but more than 700 miles from where Berreth, 29, was last seen in Woodland Park, Colorado.
Frazee, who did not live with Berreth, has said he last saw her on Nov. 22, when they met to handoff Kaylee. He said he last heard from her by text on Nov. 25, the same day her phone last pinged in Idaho.
Doss Aviation, where Berreth works as a flight instructor, also said they received a text message from her on Nov. 25. In the message, she was asking for time off.
She wasn't reported missing until Dec. 2 by her mother.
Investigators searched Frazee's home on Dec. 14 and arrested him on Dec. 21. He's being held at the Teller County Jail. He appeared in court Friday afternoon, where the defense received more information about the case and was granted more time to prepare before the next hearing. A Jan. 29 hearing was pushed to Feb. 19.
Kaylee in custody limbo:
Kaylee was placed in the care of Berreth's parents when Frazee was arrested, and they have twice been granted temporary custody of her.
In a closed hearing at a Colorado court Thursday, a judge ruled Kaylee, would remain in legal custody of the Teller County Department of Human Services, but in the physical custody of Berreth's parents.
The court is waiting to "review discovery in criminal case before proceeding further," records said.
Berreth's parents attended the hearing by phone. Frazee appeared in person.
Frazee's parents also appeared in person and attempted to get custody of Kaylee, court documents show.
Elisha Fieldstadt is a breaking news reporter for NBC News.