Lawyers for John Middleton have a variety of challenges before courts at various levels in an effort to keep him from being executed tonight.

Middleton is to die for three northwest Missouri murders in 1995.   The lethal injection is to start at a minute past midnight tonight. But Middleton’s lawyers question his mental capacity and say he’s not mentally competent to be executed.

Furthermore, says lawyer Joe Perkovich, new evidence suggests that Middleton was in jail in Iowa on the day one of the victims was murdered. And he says there’s a new witness who claims others admitted the murders to him. “In various ways law enforcement were aware of him as a witness and were aware that he had information that was extremely helpful to Mr. Middleton’s defense but suppressed it,” he says.

He says Middleton’s lawyers learned of the suppression by going through the records of the case.

Perkovich says Middleton should get a new trial. He had asked Governor Nixon to convene a clemency panel to review the case, saying Nixon isn’t capable of deciding on clemency since he was the Attorney General when Middleton was convicted. But he says there has been no direct response to the request.

AUDIO: Perkovich interview 14:47