Defense in child murder case says woman should be in DMH custody

COLUMBIA, Mo. (KMIZ)

The defense in a child murder case out of Benton County claims a woman accused in the case should be held by the Department of Mental Health.

Kourtney Aumen, 26, of Lincoln, Missouri, is charged with first-degree murder, child abuse, two counts of armed criminal action, two counts of first-degree endangering the welfare of a child and one count of first-degree assault. Her case was moved to Webster County last year.

She and others were accused in the beating and killing of 4-year-old Jessica Mast in December 2020, previous reporting shows.

A court filing from Monday by the defense claims Aumen was deemed competent in January 2025, but the defense requested she stay at a hospital because she had 11 medications. She was allegedly ordered to the DMH’s custody on May 14, 2025, but the filing says she was never moved from the jail.

A doctor allegedly determined she was incompetent to stand trial during an evaluation at the jail on July 9, 2026, the filing says.

“It is apparent that if Defendant Aumen is to be restored to competency, those efforts must be administered in a hospital setting,” the filing states. “Additionally, to stem further the deterioration of Defendant’s mental health prior to and during the resolution of this case, her return to a Department of Mental Health facility would be in Ms. Aumen’s best interest as well as the interest of justice.”

Jessica Mast’s parents – Mary Mast and James Mast – previous pleaded guilty to a number of crimes in the case, previous reporting shows.

Aumen is being held at the Benton County Jail without bond, online jail records show. A hearing is scheduled for 1 p.m. Wednesday, Aug. 12.