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The parents of a Colorado woman who has been missing since Thanksgiving filed a wrongful death lawsuit against her fiancé, who was charged last month in the missing mother's murder.

Cheryl-Lee Ellen Berreth and Darrell Lynn Berreth filed the suit against Patrick Frazee Friday in Federal Court in Colorado.

"Upon information and belief, Frazee committed and/or collaborated to commit the murder of Kelsey Berreth," the suit states. The suit seeks damages tied to emotional distress.

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A picture of Kelsey Berreth at a vigil in Woodland Park, Colorado on Dec. 13, 2018. Kelsey Brunner / The Gazette via AP

Kelsey Berreth, 29, was last seen in surveillance video shopping with the couple's 1-year-old daughter, Kaylee, on Nov. 22. She wasn't reported missing until Dec. 2 by her mother.

Authorities have not yet located her body, but believe she is dead, and have charged Frazee with two counts of first-degree murder.

Frazee is charged with two counts because investigators have two theories about how he was connected to Berreth's death. Prosecutors contend that Frazee either ordered a robbery that resulted in Berreth's murder or premeditated and carried out the murder himself.

Affidavits connected to the case are sealed so it's unclear what evidence the prosecution has against Frazee. He is due back in court on Feb. 19.

The public defender assigned to Frazee, Adam Steigerwald, did not immediately respond to a request for comment from NBC News regarding the lawsuit.

A lawyer for the Berreth's also declined to comment, saying "our federal lawsuit speaks for itself and we will not add any detail at this time."

The Berreths have been granted physical custody of Kaylee for the time being.