The Missouri Supreme Court on Monday denied a request from a man facing execution next month for a hearing to argue that he's innocent and impaired by a traumatic brain injury.

JEFFERSON CITY — The Missouri Supreme Court on Monday denied a request from a man facing execution next month for a hearing to argue that he's innocent and impaired by a traumatic brain injury.

Walter Barton, 64, was convicted of killing an 81-year-old mobile home park manager nearly three decades ago. Barton's case has been tied up in court for years due to mistrials, appeals and two overturned convictions, and his attorney continues to maintain his innocence. The state Supreme Court in February set a May 19 execution date.

Gladys Kuehler operated a mobile home park in the southwestern Missouri town of Ozark. In October 1991, officers found Kuehler dead inside her mobile home. She had been beaten, sexually assaulted and stabbed more than 50 times.

DNA testing showed that a stain on Barton's clothing was Kuehler's blood.

Barton's attorney, Frederick A. Duchardt Jr., said Barton had blood on his shirt because he was among those who helped identify the victim. Duchardt said the conviction was also based on testimony from an unreliable witness. 

Barton sought to argue that information that would impeach the witness and offer a different theory about the blood spatter would prove his innocence, but the state Supreme Court rejected that argument in its Monday ruling. The court also ruled that Barton had not shown that he was incompetent to be executed.

Barton would be the first Missouri inmate put to death since Russell Bucklew was executed in October.