Woodland Park, Colo. -- The fiancé of ahas been arrested and charged with murder and solicitation to commit murder, officials said. Kelsey Berreth, 29, was last seen on surveillance video entering a Woodland Park grocery store on Nov. 22.
Her fiancé, Patrick Frazee, told investigators the couple met that day so he could pick up their 1-year-old daughter. They did not live together. Commander Greg Couch, a spokesman for the Teller County Sheriff's Office, told CBS News his department assisted in serving an arrest warrant on Frazee at his home in the community of Florissant, Colorado. Couch said Frazee was in the Teller County jail. The child is in protective custody and will be reunited with Berreth's family, police said.
Woodland Park police chief Miles de Young said at a press conference Friday that, based on "multiple interviews," investigators no longer believe Berreth is alive.
"We finally received enough information to implicate Patrick in his involvement in Kelsey's death," de Young said.
De Young didn't speak to a motive. He said the investigation ongoing and the work is "just beginning."
"I can tell you we understand you demand a full accounting of why this has happened, and nothing is more important to all of us than determining the circumstances surrounding Kelsey's murder and bringing Kelsey and her family justice," de Young said.
De Young described a "methodical, time-consuming, multi-state" investigation that was changing hourly, involving local, state and federal officials working nearly "around the clock" to find Berreth. He said the woman's body has not yet been located and didn't want to speculate on where it might be, but said investigators have developed information to help narrow their search.
De Young confirmed that Berreth's phone pinged in Idaho, but said investigators haven't yet recovered it. The "highly technical" case involved cell phone records and other data that also led to the arrest, he said.
De Young said investigators have recovered a number of items at Kelsey's home that were suspicious enough for investigators to believe the crime happened there, and have been searching the home "to give us additional information that leads us to different locations."
De Young wouldn't speak to what led to the solicitation charge or whether investigators believe Frazee worked with anyone, but confirmed Frazee was the only person in custody. He said further arrests were possible.
District attorney Dan May said that under Colorado law, it's a crime to solicit someone to commit another crime. A solicitation charge requires someone to take a "substantial step" towards a criminal act, but not necessarily to complete it. He said the preliminary charges against Frazee don't require investigators to specify who they believe was solicited to commit a crime, but said that would be required when formal charges are filed in about 10 days.
An arrest affidavit was sealed, according to May.
The investigation opened Dec. 2 after Berreth's mother requested a police check on her daughter. Frazee told police that Berreth, a flight instructor, last texted him on Nov. 25, the Sunday after Thanksgiving.
Her aviation company employer got a text message from Berreth's phone the same day, saying she planned to take the following week off.
Police later received data indicating Berreth's phone was near Gooding, Idaho that same day, nearly 800 miles from her home.
Patrick Frazee runs a cattle ranch on his 35-acre property. Police recently searched Frazee's property but have not provided any information about the evidence they presented to a judge for approval of the search. De Young said in a statement Sunday that a search of Frazee's property was completed.
According to property records, Berreth purchased her single-family home in Woodland Park in May.
Berreth's mother told CBS News' Nikki Battiste last week the couple was excited to get married, but hadn't set a wedding date. The woman said she last spoke to her daughter on Thanksgiving, and she seemed happy and normal.