In a highly controversial move, Alabama Death Row inmate Carey Dale Grayson was executed by nitrogen hypoxia, marking only the third-ever execution using this method.

On Thursday evening, Grayson, 50, was forced to choke on an influx of atmospheric gas fed to him via a mask while strapped to a gurney in the execution chamber at the state prison in Atmore, a small city bordering Florida and about 50 miles north of Pensacola. Grayson suffered oxygen deprivation and died.

This marked the state's sixth execution in 2024. Grayson was convicted for the brutal murder of hitchhiker Vickie Deblieux in 1994. 

Grayson raised his middle fingers and cursed at the prison warden. When the prison warden asked for his final statement, Grayson responded with an obscenity. He said: "For you, you need to ---- off." The warden turned off the microphone.

Deblieux, 37, was hitchhiking from Tennessee to her mother's home in Louisiana when she was picked up by four individuals who transported her to a secluded woodland area. There, they savagely attacked her, beating her before throwing her off a cliff.

The then-teenagers later returned to the scene to desecrate her body, stabbing her 180 times. Grayson, Kenny Loggins and Trace Duncan were all found guilty of first-degree murder and sentenced to death.

However, due to their age at the time of the crime, Loggins and Duncan had their death sentences overturned following a 2005 US Supreme Court ruling that prohibited minors from being sentenced to death for crimes, reports the Mirror US. 

On Thursday, Grayson's sentence was carried out despite a federal judge hearing testimonies in October about the horrific first two nitrogen executions in Alabama.

Grayson's lawyers argued that Alabama officials should have considered revising the procedure, stating in court filings that they "have chosen to ignore clear and obvious signs the current protocol contains major problems."

Witnesses to the first two nitrogen gas executions described the shocking scene of inmates shaking on the gurney for over two minutes, experiencing spasms and laboured breathing with long pauses until death.

Alabama Corrections Commissioner John Q Hamm previously testified that he had no concerns about the execution method, anticipating involuntary movements like spasms based on his research. The first two inmates to die by nitrogen hypoxia were Kenneth Eugene Smith and Alan Eugene Miller, who died in January and September, respectively.

Rev. Dr. Jeff Hood, a spiritual adviser for many death row inmates who witnessed Smith's execution, shared the horror he experienced.

"It looked like a fish out of water. He kept heaving back and forth, back and forth. And the mask was tied to the gurney, and so every time he heaved forward, his face was hitting the front of the mask and pressing into the mask," he said. "His eyes started to bulge. He began to turn colours. He was spitting, and mucus was coming out of his mouth and his face. He kept almost hitting his face on the front of the mask."

Lethal injection remains Alabama's primary execution method, but inmates now have the choice between that, nitrogen hypoxia, and the electric chair.

Following Smith's execution in January, Alabama has scheduled dates for other inmates who also chose nitrogen hypoxia.