- Associated Press - Tuesday, February 4, 2014

JEFFERSON CITY, Mo. (AP) - A death row inmate is again asking the Missouri Supreme Court to overturn his conviction for a 1991 killing in southern Missouri.

Walter Barton was convicted of killing 81-year-old Gladys Kuehler, who was a mobile home park manager in Ozark.

Barton’s attorney argued to the Supreme Court on Tuesday that prosecutors improperly failed to disclose that the victim’s granddaughter had been convicted of misdemeanor crimes many years after the slaying. The granddaughter was a witness at the trial, and Barton’s attorney said the misdemeanors could have been used to question her credibility.

Barton has twice previously had his conviction and death sentence overturned. His most recent conviction came from a re-trial in 2006.