DENVER – Police have arrested the fiancé of a missing Colorado mother who vanished on Thanksgiving after shopping with their daughter, and they plan to charge him with murder and solicitation to commit murder.

Kelsey Berreth’s mother reported her missing Dec. 2. Police arrested Berreth’s fiancé, Patrick Frazee, at his rural home Friday morning in the mountains west of Colorado Springs, in central Colorado. Berreth’s disappearance prompted a multi-state search and her body has not yet been found. Investigators have repeatedly searched both Frazee and Berreth's homes.

“As you can tell from the arrest, sadly, we do not believe Kelsey is still alive," Woodland Park Police Chief Miles De Young said at a press conference on Friday morning. "I can't stress enough that this is a difficult time for Kelsey's family."

De Young said investigators believe Frazee, 32, is the last person to have seen Berreth, 29, in person, when the two exchanged their 1-year-old daughter, Kaylee. De Young said Kaylee is being held in protective custody and will be reunited with Berreth's family members. Police have not indicated any motive, and Frazee will be formally charged within 10 days.

Police said Frazee told them Berreth, a flight instructor, last texted him on Nov. 25. And her employer said they received a text message from her phone that same day saying she planned to take the next week off. Police said phone-location data indicated Berreth's phone was near Gooding, Idaho, nearly 800 miles from her home in Woodland Park. Berreth has family in the area. Frazee is a rancher who works with horses.

Many court records surrounding the case are sealed due to the ongoing investigation. Police said they haven't ruled out additional arrests, citing the charges of solicitation of murder Frazee faces.

Last week, Frazee said through his attorney that he voluntarily released his phone to law enforcement for a search and provided DNA swabs and photographs. Friday afternoon, Frazee appeared briefly in court to be advised of his rights; he's now being represented by the public defender's office.

There's a $25,000 reward being offered for information in the case, police said.