07/15/2014 11:17 am ET Updated Jul 15, 2014

Federal Judge Stays Execution Of Killer John C. Middleton

A Federal judge has granted a stay of execution for a Missouri inmate on death row.

John C. Middleton, 54, was scheduled to die by lethal injection Wednesday, in what would have marked the sixth execution in Missouri in 2014.

In a petition filed July 15, Middleton's attorneys argued that their client is mentally ill, quoting an affidavit by a psychiatrist that states:

"[Middleton] lacks a rational understanding of the reason for the execution and is therefore not competent to be executed due to a diagnosis of delusional disorder, a psychotic mental illness.”

Middleton was convicted of murdering three men in 1995, but his lawyers claim he is innocent. A previous petition filed by his attorneys says that he was in an Iowa jail 40 miles away when one of the killings occurred.

“It’s hard to think of a more ironclad alibi than that,” the prisoner’s attorney, Joseph Perkovich, told The Guardian.

That petition and others were rejected, the newspaper reported.

This is a developing story.