Marlene Wynn pleaded guilty last week to second-degree murder and armed criminal action stemming from the alleged killing of her mother in 2018.

Wynn, 55, of Warrenton, was arrested in September 2018 after her 85-year-old mother, Mildred Brune, was found deceased in her home on Cambridge Drive with severe head trauma and stab wounds.

Wynn reportedly was found in the home and identified as the suspect in the killing, having made multiple statements that she had killed her mother using a knife and a cane, police at the time said.

Several weeks after the killing, Warren County Associate Judge Richard Scheibe ordered Wynn to undergo a mental evaluation through the Missouri Department of Mental Health (DMH). The order at the time stated the court had reason to believe Wynn might have a “mental disease or defect” that would prevent her from understanding the court proceedings or assisting in her own defense.

According to First Assistant Prosecutor Rachel Smith, the legal counsel for Wynn had planned to submit a plea of not guilty by reason of insanity, which delayed the case significantly while Wynn was evaluated. 

Once the state hospital had submitted its report on Wynn’s fitness to stand trial, Smith said she and Warren County Prosecuting Attorney Hannah Dunakey decided they would not accept that defense and that Wynn would stand trial. 

Smith said the prosecutor’s office had planned to pursue charges of armed criminal action and first-degree murder. 

Roughly a week before that trial was set to begin, Smith said that Wynn came forward and said she wanted to accept responsibility and enter a guilty plea. As a part of that plea agreement, prosecutors lowered the charges to armed criminal action and second-degree murder.

“Given the nature of the offense, given the nature of the underlying issues, we went ahead and allowed her to plead to murder in the second degree and agreed upon a sentence of 25 years,” said Smith. 

Smith said that Wynn’s willingness to admit guilt, the relationship between her and the victim and the attempts to use her mental illness as a defense led the prosecutor’s office to accept a plea agreement. 

“Those things combined to make it a little more complicated than a murder,” said Smith. 

She did elaborate saying the case was more focused on how severe Wynn’s punishment would be given the strength of the evidence against her. 

“It was never a case of who did it in this situation, it was just what she would be found responsible for and where she’d serve her time,” said Smith. 

As long as the court accepts the agreement, Wynn will be sentenced at 9 a.m. on Dec. 5. The victim’s family will be afforded the opportunity to speak before a decision is made.