Gilbert Postelle had no last words before Oklahoma put him to death on Thursday. 

He simply shook his head “no” and closed his eyes before the lethal injection drugs were pumped into his body.

Postelle, 35, was the fourth person put to death under Oklahoma’s revised lethal injection protocol. The Department of Corrections issued the new three-drug protocol in 2020 following a years-long moratorium after a series of execution mistakes.

The first drug, midazolam, a sedative, appeared to take hold over Postelle quickly. Postelle glanced at media witnesses a few times after the process began at 10 a.m. By 10:02 a.m., his eyes were glazed over and his mouth frozen open. 

Postelle appeared to breathe periodically, but stopped soon after a physician entered the room and declared him unconscious. 

Department of Corrections Director Scott Crow declared Postelle dead at 10:14 a.m. Crow later said the execution took place without complication.

Postelle was sentenced to death for his role in a quadruple homicide on Memorial Day 2005 in Oklahoma City. Killed were Amy Wright, Donnie Swindle, James Alderson and Terry Smith. Postelle believed the group was responsible for a motorcycle wreck that had injured his father. 

Swindle’s sister Shelli Milner read a statement to reporters following the execution, saying that it was “not a joyous day for anyone” and that Postelle’s death “did not end anyone’s suffering.”

“Today ended one monster’s life who stole four innocent people’s lives,” Milner said. “His family grieves as our families have grieved for 17 years. To know that he will never walk this Earth again does give me a little more peace than I had yesterday.”

Milner closed by referencing the family of Paul Howell, who was shot to death in 1999 in Edmond. Julius Jones was convicted of first-degree murder and sentenced to death for Howell’s killing, but Gov. Kevin Stitt granted him clemency last year.

“You should have had this opportunity a few months ago and my heart goes out to you and to all the families who are going through this and have to live with this pain,” Milner said.

Jones maintained his innocence for years. His case drew national headlines and his guilt was questioned by his family, a large number of advocates and state lawmakers.

Gilbert Postelle’s brother David Postelle was sentenced to life without parole for his role in the quadruple slaying, while father Earl Postelle was eventually declared incompetent to stand trial because of the injuries he had suffered in the motorcycle accident. Gilbert Postelle was sentenced to death after evidence showed he followed Wright and Alderson and shot them from behind as they tried to escape.

Gilbert Postelle’s attorneys told the Oklahoma Pardon and Parole Board in December that he deserved leniency or a new trial because he was only 19 at the time of the killings and had an IQ of 76. 

His attorneys also argued that Postelle had been influenced by his father to begin using methamphetamine at the the age of 12. After the killings, Postelle said his father encouraged him and his brother, saying “That’s my boys.”

But the courts have denied Postelle’s attempts to leave death row. In 2011 the Oklahoma Court of Criminal Appeals ruled against Postelle and last December his appeal for clemency was denied by the Pardon and Parole Board.

Postelle’s execution is the last before the start of the federal trial later this month over Oklahoma’s lethal injection procedures. Twenty-nine death row inmates are suing the state, claiming the protocol could cause them pain and violate a constitutional ban on cruel and unusual punishment. 

John Grant was the first person put to death under the new protocol in October. Grant vomited and convulsed during the execution, according to media witnesses. But Crow attributed Grant’s distress to food the man had eaten shortly before being put to death. 

In December, the state put Bigler Stouffer to death, who did not exhibit signs of distress during his 13-minute execution.

Both Grant and Stouffer had pulmonary edema, or heavy, liquid-filled lungs, following their executions, according to autopsy reports. 

The autopsy reports raise questions about midazolam, the first drug in Oklahoma’s three-drug protocol. Unlike the drugs Oklahoma used in past executions, midazolam is a sedative and not a painkiller. Critics say midazolam can cause the condemned to convulse, gasp, cough and wheeze during executions, possibly from excess fluid in the lungs.

Another man, Donald Grant, was executed in January, but a medical examiner’s report on his death is not yet complete.