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Mother of Benton County child killed takes plea deal, could avoid murder charge


The mother of a 4-year-old girl who died after several weeks of alleged abuse accepted a plea deal in the case on Wednesday.

Mary Mast, 31, pleaded guilty to first-degree child endangerment in Benton County court. Prosecutors agreed to drop seven other charges against her, including first-degree murder, as long as Mast testifies against her co-defendants in the case. Defense attorney John Rogers said in court that the state will also recommend a five-year prison sentence for Mast when all cases are finished.

Judge Brandon Baker set an April 5 court hearing to make sure the case was still on track.

Mast and three others are accused of beating and eventually killing 4-year-old Jessica Mast in December 2020. She was arrested alongside her husband and Jessica's father, James Mast, and their neighbors, Kourtney Aumen and Ethan Mast. Law enforcement officials claim Aumen was the one who encouraged the abuse of Jessica and Mary's children, claiming it would keep a "demon" from inhabiting them.

Jessica Mast.
Courtesy Kidwell-Garber Funeral Homes

Benton County assistant prosecutor Rod Richardson said the child endangerment charge Mary Mast pleaded guilty to stems from the abuse done to her son, who survived. Sheriff's deputies claim Mast and the others hit the boy, leaving scars. A video on Ethan Mast's cellphone allegedly shows Mary hitting the child with a wooden spoon and scolding him when he grabbed the spoon from her.

The plea agreement means Mary Mast will not face charges tied to the death of her daughter. Prosecutors claim Jessica Mast died when she was taken out and dunked into a pond. Law enforcement said Mary admitted to submerging her in the water at Ethan Mast and Aumen's direction.

Deputies said they found on bruises on both Mary and James when they first interviewed them, including bruises on Mary Mast's face.

Five years is the minimum sentence allowed for first-degree child endangerment. Rogers said the agreement bars him from recommending probation for Mary Mast.

"The mother got off super light," said JC Vandergriff, a member of Guardians of the Children, a non-profit organization for motorcycle enthusiasts. He said he hopes the guilty plea leads to others being held responsible and for people to say something if they suspect child abuse.

"We can't fix the courts, we can't influence the courts, all we can do is show our support for the victims and the victims' family," Vandergriff said.

(Editor's note: This story has been updated to reflect the abuse claims involving the Masts' children.)

Article Topic Follows: Crime

Lucas Geisler

Lucas Geisler anchors the 5 p.m. show for ABC 17 News and reports on the latest news around mid-Missouri at 9 and 10 p.m.


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