Two members of congress from Missouri are calling on their state's governor to stop Tuesday's scheduled execution of a Navy veteran convicted of murdering his ex-girlfriend and her husband in 2009.

David Hosier, 69, was "suffering from significant brain damage from a stroke" at the time of the killings and his lawyers "failed to fully present this crucial information" at his trial, Reps. Cori Bush and Emanuel Cleaver said in a Friday letter to Gov. Michael Parson.

One juror has said Hosier's condition would have affected his sentence, the progressive Democrats said, and they urged Parson, a Republican, to intervene and "immediately" grant Hosier clemency.

"Each of us is more than the worst thing we've ever done. The same is true for Mr.Hosier," they wrote in the letter posted online by the Hill.

The Missourians to Abolish the Death Penalty group also submitted a petition with nearly 7,000 signatures that seeks to block Hosier's execution, the Missourinet website reported Thursday.

A spokesperson for Parson didn't immediately respond to an inquiry from HNGN on Monday.

Hosier was convicted in 2013 of fatally shooting Angela and Rodney Gilpin in the hallway of their apartment building in Jefferson City, Missouri, in September 2009, shortly after she ended an affair with him.

The death row inmate maintains his innocence in the face of circumstantial evidence that included statements he made to others threatening to harm Angela Gilpin in the days before the killings, according to the Associated Press.

Police also found an application for a protective order against Hosier in her purse and another another document in which she expressed fear he might shoot her and her husband.

Hosier was arrested after a police chase in Oklahoma, where authorities seized 400 rounds of ammunition and 15 firearms, including submachine gun made from a kit that was later linked to the killings.

"How can you find a person guilty beyond a reasonable doubt and sentence that person to die when you have no witnesses to a crime, you have no fingerprints to tie this person to a crime, you have no DNA that ties this person to a crime?" the AP quoted Hosier as saying.

Last month, Hosier was hospitalized for apparent heart failure but he was released following treatment, according to the Kansas City Star.