GIRL, 4, DIED AFTER BEING BEATEN AND DUNKED IN A FREEZING POND — NOW HER NEIGHBOR HAS PLEADED GUILTY

Jessica Joy Mast was just four years old when she died in Missouri in December 2020. Nearly six years later, a woman accused of abusing the little girl has admitted to second-degree murder and first-degree assault, bringing a major development in a case that shocked the community.

A heartbreaking case involving the death of a four-year-old girl has returned to the headlines after one of the adults accused in connection with her death entered guilty pleas.

Jessica Joy Mast died in December 2020 after suffering severe injuries in Warsaw, Missouri. According to court records and reports from the investigation, the child had been beaten and repeatedly forced into a freezing farm pond.

Kourtney Taylor Aumen, now 27, pleaded guilty to second-degree murder and first-degree assault on October 5, 2026. She had previously faced more serious charges, including first-degree murder, and was due to stand trial later this month.

Aumen is scheduled to be sentenced on December 21, 2026.

A horrifying ordeal in freezing temperatures

Investigators said Jessica and her two-year-old brother were subjected to abuse by Aumen and another neighbor, Ethan Mast, 41, who was not related to the children.

According to accounts given to investigators, the adults claimed that Jessica’s mother was possessed by a demon and that the children could also become possessed.

Prosecutors said the children were beaten and that Jessica was repeatedly dunked into a nearby pond while temperatures hovered around 40°F (approximately 4°C).

Jessica’s parents, James and Mary Mast, were reportedly threatened with violence if they tried to intervene. Her father told investigators that the adults threatened to beat or shoot them if they interfered.

The allegations formed part of the investigation into the events that led to the little girl’s death.

The discovery that shocked investigators

A Benton County sheriff’s deputy was called to the family home following reports of a possible domestic disturbance.

Inside, the officer was directed upstairs, where Jessica was found lying on the floor beside a set of bunk beds, wrapped in a pink blanket.

Investigators reported that the child’s body showed extensive bruising and open wounds. Her hair was still wet, and vomit was found nearby.

Jessica was already dead when the deputy arrived.

The discovery prompted an investigation into the treatment of Jessica and the other members of her family. Authorities later described the incident as a disturbing case involving beliefs about demonic possession.

Other family members and the second defendant

Aumen was not the only person charged in connection with the case.

Ethan Mast also pleaded guilty to second-degree murder. Jessica’s father, James Mast, pleaded guilty to second-degree murder and first-degree assault in 2024, but subsequently sought to withdraw his plea. Recent reporting says he has continued to challenge it through further legal motions.

Jessica’s mother, Mary Mast, pleaded guilty to child endangerment in 2023.

Their cases have followed separate legal paths, and the latest reporting indicates that further proceedings remain relevant to the family’s legal aftermath.

Justice delayed, but the case is not over

Aumen’s guilty pleas mark a significant development in a case that began nearly six years ago. Her sentencing is scheduled for December 21, when the court will determine the punishment for the offenses to which she admitted guilt.

For Jessica’s loved ones, however, no court decision can restore the little girl whose life ended before she had the chance to grow up.

The case has also raised painful questions about the vulnerability of children and the circumstances in which adults around them failed to protect them.

Jessica was only four years old. Her name is now at the center of a case that continues to unfold in court, years after the events that took her life.

As Aumen awaits sentencing, the legal proceedings surrounding Jessica’s death continue — while the little girl at the heart of the case remains the person whose loss cannot be undone.

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