Retired detective Steve Rogers appeared on "America's Newsroom" Monday to weigh in on the disappearance of Kelsey Berreth, which police have called "suspicious.

An anonymous donor came forward with a $25,000 reward on Saturday for information leading to the 29-year-old mother, who was last seen on Thanksgiving Day entering a Safeway store in Woodland Park.

Berreth was reported missing by her mother 10 days after she was last seen and heard from. Authorities have turned their attention to Berreth's fiancé, Patrick Frazee, scouring his home and property. Frazee currently has custody of the couple’s 1-year-old daughter. reported:

In surveillance video released Monday, Berreth was seen entering the Woodland Park supermarket — the last time she was publicly spotted. Three days later, her cellphone showed the mother had sent a text to her boss at Doss Aviation saying she wouldn’t be at work the next week. She also sent a text to Frazee — but the content of that message also was not released.

The last location her cell phone pinged from was in Gooding, Idaho, nearly 700 miles away from her home.

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Rogers said the police have conducted a "textbook investigation" so far, by starting out by looking at Berreth's home and the people with whom she was closest.

He said investigators will do a full forensic analysis of Berreth's computers, cell phones, text messages, emails and so on.

"The question that I know the police are trying to answer is: Why did it take 10 days, ... why did it take that period of time for somebody to report her missing?" Rogers said.

He said he believes investigators may have obtained a piece of evidence that they are not publicly revealing, in order not to compromise their investigation.

"The police are on track. They're doing a good job with this, but they're being careful not to release too much information, so that the case is not compromised," Rogers said. "Somebody knows something. And I'm sure the police are onto that person. That's why they don't want to say too much."

Watch more from Rogers above.

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