OKLAHOMA CITY (AP) — The U.S. Supreme Court on Wednesday denied a last-minute appeal filed by Oklahoma death row inmate Benjamin Cole, paving the way for him to receive a lethal injection on Thursday.

Cole, 57, was convicted and sentenced to death for killing his 9-month-old daughter Brianna Cole by forcibly bending the infant backward, breaking her spine.

Three photos of Brianna Cole, who was killed by her father Benjamin Cole

On December 20, 2002, Benjamin Cole told investigators that he was trying to get his 9-month-old daughter to stop crying when he grabbed the baby by the ankles and pushed her legs toward her head until she flipped over.

For years, Cole’s attorneys have said that he has suffered from untreated paranoid schizophrenia, and more recently, his attorneys have claimed that Cole’s condition has deteriorated significantly while on death row.

Cole’s attorneys have not disputed that he killed the infant, but they say he is severely mentally ill and that has brain damage that worsened while he has been in prison.

“The state courts’ acknowledgment that experts have reached conflicting opinions about Ben Cole’s competency should have been all they needed to order a full competency hearing,” said Emma Rolls, one of Mr. Cole’s attorneys. “This is particularly true given the implausibility of Dr. Orth’s claim to have had a lengthy conversation with Mr. Cole, which conflicts with the reports of prison staff, medical personnel, and others who have been unable to have any meaningful interaction with Mr. Cole for years.”

Cole’s attorneys filed a lawsuit in the U.S. District Court for the Northern District of Oklahoma late Tuesday seeking a competency hearing for him.

On Monday evening, his attorneys also filed a petition for writ of certiorari asking the United States Supreme Court to intervene.

Cole’s attorneys say both the federal complaint and petition for writ of certiorari assert that the State of Oklahoma would violate his rights under the United States Constitution by executing him despite his incompetency.

“No execution should proceed until a court has heard expert testimony and carefully considered all the evidence of Ben Cole’s mental state to determine whether or not he is competent to execute,” said Rolls.

A state panel rejected Cole’s bid for clemency in September, and a district court judge in Oklahoma determined that he was competent enough to be executed.

Cole is scheduled to be executed on Oct. 20, 2022.

Cole’s execution would be the sixth since Oklahoma resumed carrying out the death penalty in October 2021.