(CNN) - Colorado investigators trying to find Kelsey Berreth, a 29-year-old mother who went missing on Thanksgiving Day, have started searching her fiancé's home and property, authorities said Friday.
About 75 officers are combing the 30-plus acres outside Woodland Park, Colorado where Patrick Frazee lives, a law enforcement source told CNN. Frazee was at the home, which he does not share with Berreth, when officers arrived, but later left, the source said.
Woodland Park Police Chief Miles De Young provided few details at a news conference, declining to say what investigators are looking for or what prompted them to search that location. The search warrant is sealed.
But the chief said the disappearance of Berreth, a flight instructor, is considered "suspicious" and that authorities think "she is not intentionally avoiding attempts to find her."
De Young urged Frazee to consent to a face-to-face interview with police instead of communicating through his lawyer.
The attorney for Frazee, Jeremy Loew, issued a statement in which he said his client "continues to cooperate with law enforcement."
"We understand that a search warrant was executed on Mr. Frazee's property," Loew said. "Mr. Frazee was never asked to voluntarily participate in this search. We encourage law enforcement to take whatever steps it deems necessary to find Kelsey Berreth and to be able to exclude Patrick Frazee as a possible suspect in this missing person investigation. Mr. Frazee will continue not to participate in any interviews with the media and instead focus on parenting the child he shares with Ms. Berreth."
On Wednesday, Frazee's lawyer said his client had voluntarily released his phone to be searched and allowed officers to take a DNA sample.
Frazee told police he last saw Berreth on November 22, when he picked up their 1-year-old daughter. That makes him the last known person to report seeing Berreth alive.
Police said they have surveillance video of Berreth shopping with her daughter that day at a Woodland Park supermarket.
Police have said Berreth's employer received a text from her phone November 25 saying she wouldn't be able to work that week. Frazee also said she texted him that day, but the contents of that text haven't been released.
A week after that, she was reported missing. Woodland Park police began their search on December 2, when Berreth's mother, Cheryl Berreth, alerted them of her daughter's disappearance.
Kelsey Berreth's phone was tracked to a location near Gooding, Idaho, and Berreth has family in that state, De Young said. Gooding is roughly 800 miles northwest of Woodland Park.
"She's not the kind that runs off," Cheryl Berreth said. "This is completely out of character. Kelsey loves her God, she loves her family and friends, and she loves her job. She's reliable, considerate and honest."
On Friday, De Young said it is "absolutely a possibility" that Berreth is still alive.
"That's our hope," he said.
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