The family of an Oklahoma convicted killer set to be executed by lethal injection on Thursday is making a last-ditch effort to save his life.

Michael Smith confessed to killing 40-year-old Janet Moore and 24-year-old store clerk Sharath Pulluru in separate instances in 2002.

His lawyer argued that the confessions were coerced and that Smith has mental disabilities and wasn't fit to stand trial or be executed.

The prosecutors said that Smith was a cold-blooded killer and said his confession was corroborated by evidence at both murder scenes.

According to court records, Smith is a member of the Crips gang in Oklahoma City.

In November 2000, three members of the gang attempted to rob a convenience store and the store owner shot and killed one of the robbers.

The two other robbers were arrested and set for trial in February 2022. Two days before the trial, Smith went to the apartment of Janet Moore because he believed her son was a police informant. He ended up killing her.

He then went to a convenience store, killed clerk Sharath Pulluru, took money from the register and set fire to Pulluru's body, the McAlester News-Capital reported.

Smith's relatives were delivering a petition to Gov. Kevin Stitt's office on Wednesday, asking him to call off the execution.

The family claims there is new evidence in the case.

A private investigator claims a state witness who testified during the trial says she was coerced into her testimony, KOCO-TV reports.

Last month, the parole board denied a clemency request by Smith.

"I am pleased the Pardon and Parole Board denied clemency for the ruthless killer who took Janet Moore and Sharath Pulluru away from their families," Oklahoma Attorney General Gentner Drummond said in a statement at the time.

If the execution is carried out, it will be the first one carried out in the state this year.