MARYLAND HEIGHTS, Mo. - Time is running out for 44-year-old Lance Shockley. 

He’s scheduled to die by lethal injection tomorrow at 6 p.m.--the first execution in the state for 2025. Shockley was convicted of the 2005 murder of Missouri State Highway Patrol Sgt. Carl Dewayne Graham Jr. Graham Jr. was ambushed and killed in his own home and three days later Shockley was arrested.

Shockley was found guilty of entering Graham's home, where he first shot the trooper from behind with a rifle, severing his spinal cord and paralyzing him before delivering fatal shotgun blasts to Graham's face and shoulder.

A judge sentenced Shockley to death after a jury deadlocked. Advocates have pointed to ineffective legal counsel, juror misconduct, and the circumstantial nature of the evidence.

Governor Mike Kehoe denied Shockley’s clemency, announcing Monday morning his execution will move forward Tuesday night. 

The court case has catalyzed national studies like one out of UC Irvine’s School of Psychology.

Heidi Moore, executive director of Missourians to Abolish the Death Penalty, told FOX 2 about the study's findings.

 "The findings even said that for people in Missouri who support the death penalty, they still thought that lance shockley should be given clemency,” Moore said.

A petition with more than 31,000 signatures has been presented to the governor’s office calling for clemency.

FOX 2 reached out to the Missouri Department of Corrections and the Missouri Attorney General for more information on why they are fighting his selection.