A new court filing cites a suspected motive in the presumed murder of Colorado mom Kelsey Berreth, and also accuses the suspected killer of lying about the missing woman’s whereabouts.

KKTV 11 obtained the court filing of the wrongful death lawsuit filed by Berreth’s parents against Patrick Frazee, the father of Berreth’s 1-year-old daughter who was arrested on suspicion of murdering Berreth.

According to the lawsuit, the plaintiffs Berreth’s parents believe Frazee murdered Berreth because he wanted full custody of their daughter Kaylee. From the documents:

“Upon information and belief, Frazee had motive to kill Kelsey in that he wanted full custody of KB and/or Kelsey to leave KB with him and Kelsey would not agree; Upon information and belief, Frazee had an opportunity to kill Kelsey or have Kelsey killed in that he had her keys and, because he had her gun, she was vulnerable to an attack.”

As reported by the Denver Post, the plaintiffs also accused Frazee of knowingly sharing and encouraging the spread of false information about Berreth and their relationship. From the filing: