on Thanksgiving Day after dropping off her young daughter with her fiance. On Friday, police searched his home.
After searching the Florissant, Colorado, property of Patrick Frazee, police now want to question him.
"We are asking Patrick to sit down with investigators since he is the last person to talk with Kelsey," Woodland Park police Chief Miles De Young said Tuesday.
The last image of Berreth with her 1-year-old daughter was captured on surveillance video at a supermarket on Thanksgiving Day. Frazee, the father of Berreth's child, does not live with them.
"Do you think for a nano-second she may have gone on her own?" CBS News asked her mother, Cheryl Berreth.
"I seriously doubt it. I guess anything is possible but given that she is dedicated to her job, her daughter, her family, I just can't see she would go anywhere without somebody knowing."
Berreth, 29, was last seen 22 days ago. She was reported missing on December 2. Three days after Berreth vanished, her phone pinged from Gooding, Idaho, which is 600 miles away.. One to her fiance, the other to her employer saying she would not be at work the following week.
Frazee's attorney, Jeremy Loew, said his client has been cooperating with the investigation. Loew has said that Frazee has provided police with DNA samples and access to his cellphone, the Associated Press reported.