ST. LOUIS (AP) — Attorneys for Missouri death row inmate Earl Ringo Jr. are asking Gov. Jay Nixon to halt the execution scheduled for next week over concerns that race was a factor in Ringo's conviction and death sentence.

Ringo, who is black, was convicted of killing two people in a Columbia restaurant robbery in 1998. Attorney Kay Parish says Ringo was tried by a white judge and sentenced to death by an all-white jury. Her request to Nixon on Thursday also asks that the governor appoint an independent board of inquiry to examine the role race played in the case.

Messages seeking comment from Nixon's office were not immediately returned.

Ringo is scheduled to die by injection at 12:01 a.m. Wednesday. He would be the ninth Missouri inmate executed since November.