Father of Benton County, Mo. 4-year-old girl who died in 2020 accepts guilty plea deal

BENTON COUNTY, Mo. (KY3) - The father of a Benton County four-year-old girl who died in 2020 has accepted a plea deal offered by prosecutors.

According to court officials, James Mast accepted a guilty plea deal Monday to second-degree murder and first-degree assault. If Mast fully cooperates and doesn’t renege on the terms of his plea agreement, his six other counts will be dismissed.

Mast was originally charged with first-degree murder, three counts of armed criminal action, abuse or neglect of a child, first-degree assault, and two counts of endangering the welfare of a child.

According to court officials, when the sentencing hearing comes - it has not been scheduled- prosecutors will recommend “no more than life sentences” on both counts for Mast to be served concurrently.

Mast will not be sentenced until co-defendant Kourtney Aumen’s case is resolved. The four people charged in the case are Mary Mast and James Mast, Kourtney Aumen, and Ethan Mast (no relation).

On December 19, 2020, Mast’s four-year-old daughter drowned after being dunked into an icy pond and beaten to death to remove a “demon.”

Benton County deputies responded at 1 a.m. on December 20 to a rural home near Cole Camp and found the 4-year-old wrapped in a blanket on a bedroom floor.

Investigators said the girl was already dead and had “severe purple bruising” over her body, along with ruptured blisters. Sheriff Eric Knox said the girl’s parents also had been beaten along with a 2-year-old child. An infant son of the couple was apparently unharmed.

Ethan Mast told investigators that he and Aumen used a leather belt to beat the girl, the statement said. She was then taken to a pond behind the home, where she was “dunked” in the water on a day when high temperatures were in the 40s.

Ethan Mast said everyone then returned to the victims’ home. It wasn’t clear when the child died. An autopsy will determine the cause of death. Knox said evidence indicated she was beaten to death.

Mary Mast entered a guilty plea in January 2023 and is awaiting a sentencing date. Ethan Mast entered a guilty plea in February 2022 and is awaiting a sentencing date. Kourtney Aumen is currently being held on a mental health commitment order.

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