Patrick Frazee, allegedly the last person to see 29-year-old Kelsey Berreth, was arrested at his home and cattle ranch in the central Colorado community of Florissant, Teller County sheriff's Commander Greg Couch said.
Kelsey Berreth, 29, was last seen in a grocery store near her home in Woodland Park, about 15 miles (24 kilometers) from Florissant.
De Young said in a press conference at the time that he could not reveal what, if anything, was found during the search, as the warrants were sealed.
Berreth went missing nearly a month ago after last being seen shopping with her 1-year-old daughter on Thanksgiving Day.
Although no body has been found, investigators say they do not believe Kelsey Barreth is alive.
Authorities also declined to elaborate on the solicitation of murder charge, how they believe Berreth was killed or any other aspect of the investigation.
United States charges Chinese nationals with computer hacking of Navy, NASA
"This case is significant because the defendants are accused of targeting and compromising Managed Service Providers, or MSPs". It is understood that the MSPs did not always respond to warnings as robustly as authorities would have liked.
A lawyer from the public defender's office was appointed to represent Frazee, according to court documents. The couple never lived together, De Young said previously.
"Her voice was fine", Cheryl said, noting that they discussed "small things" such as a recipe.
The disappearance of the young pilot mystified family and friends and led to national social media seeking any information on her whereabouts.
The fiancé of missing Colorado mom Kelsey Berreth has been arrested in connection with her disappearance.
Surveillance video showed her entering the store on Thanksgiving Day with what appears to be the couple's daughter in a baby carrier.
Mr Frazee had told police that the couple met sometime that afternoon so he could pick up the child.
De Young said the girl is in protective custody and will be turned over to Berreth's family.
Tour de France champion Geraint Thomas wins BBC award
Three Lions head coach, Gareth Southgate was named Coach of the Year after guiding England to their first World Cup semi-final appearance in twenty-eight years.
Frazee has not spoken publicly but his attorney, Jeremy Loew, said last week that he was cooperating with law enforcement. Loew wasn't available for comment Friday. Investigators were working to recover it.
A text from her phone to her employer, sent on November 25, said that she would not be coming into work that week.
A week after, on December 2, Berreth was reported missing after her mother, Cheryl, alerted police of her daughter's disappearance. Investigators found all of her suitcases, personal items and vehicles at her home.
Berreth's employer, Doss Aviation, received a text message from her cellphone that day saying she planned to take the following week off.
Cheryl Berreth told NBC News that her daughter's relationship with Frazee had been good and loving.
The reward for information leading to finding Berreth is $25,000, Woodland Park police said.
A multijurisdictional task force made up of numerous law enforcement agencies, including the Federal Bureau of Investigation, served the warrant at Frazee's 35-acre ranch in Florissant.
NASA says Saturn's rings are disappearing at 'alarming speed'
Scientists had previously found Saturn's rings were losing mass from data sent back from the Voyager 1 and 2 spacecraft. As the planet progresses in its 29.4-year orbit, the rings are exposed to the Sun to varying degrees.