ATMORE, Ala. (AP) — An Alabama man convicted in the 1994 killing of a hitchhiker cursed at the prison warden and made obscene gestures with his hands shortly before he was put to death Thursday evening in the nation’s third execution using nitrogen gas.

Carey Dale Grayson, 50, was executed at the William C. Holman Correctional Facility in southern Alabama. He was one of four teenagers convicted of killing Vickie DeBlieux, 37, as she hitchhiked through the state on the way to her mother’s home in Louisiana. The woman was attacked, beaten and thrown off a cliff.

Alabama began using nitrogen gas earlier this year to carry out some executions. The method involves placing a respirator gas mask over the face to replace breathable air with pure nitrogen gas, causing death by lack of oxygen.

Alabama Corrections Commissioner John Q. Hamm said the nitrogen flowed for 15 minutes and an electrocardiogram showed Grayson no longer had a heartbeat about 10 minutes after the gas began flowing.

Like two others previously executed by nitrogen, Grayson shook at times before taking a periodic series of gasping breaths.

The victim's daughter told reporters afterward that her mother had her future stolen from her. But she also spoke out against the decision to execute Grayson and “murdering inmates under the guise of justice.”

The curtains to the execution room were opened shortly after 6 p.m. Strapped to a gurney with a blue-rimmed gas mask on his face, Grayson responded with an obscenity when the warden asked if he had any final words. Prison officials turned off the microphone. Grayson appeared to speak toward the witness room where state officials were present, but his words could not be heard. He raised both middle fingers at the start of the execution.

It was unclear when the gas began flowing. Grayson rocked his head, shook and pulled against the gurney restraints. He clenched his fist and appeared to struggle to try to gesture again. His sheet-wrapped legs lifted off the gurney into the air at 6:14 p.m. He took a periodic series of more than a dozen gasping breaths for several minutes. He appeared to stop breathing at 6:21 p.m., and then the curtains to the viewing room were closed at 6:27 p.m.

Grayson was pronounced dead at 6:33 p.m.

DeBlieux’s mutilated body was found at the bottom of a bluff near Odenville, Alabama, on Feb. 26, 1994. She was hitchhiking from Chattanooga, Tennessee, to her mother’s home in West Monroe, Louisiana, when the four teens offered her a ride. Prosecutors said the teens took her to a wooded area and attacked and beat her. They returned to mutilate her body.

A medical examiner testified that her face was so fractured that she was identified by an earlier X-ray of her spine. Investigators said the teens were identified as suspects after one of them showed a friend one of DeBlieux’s severed fingers and boasted about the killing.

DeBlieux’s daughter Jodi Haley spoke with reporters at the media center on prison property after the execution. Haley was 12 when her mother was killed, She said her mother had her life and future stolen from her.

"She was unique. She was spontaneous. She was wild. She was funny. She was gorgeous to boot,” Haley said of her mother.

She said Grayson was abused in every possible way in his youth but “society failed this man as a child, and my family suffered because of it.”

“Murdering inmates under the guise of justice needs to stop,” she said, adding that "no one should have the right to take a person's possibilities, days, and life."

Gov. Kay Ivey said afterward she was praying for the victim’s loved ones to find closure and healing.

“Some thirty years ago, Vicki DeBlieux’s journey to her mother’s house and ultimately, her life, were horrifically cut short because of Carey Grayson and three other men," Ivey said in a statement. “She sensed something was wrong, attempted to escape, but instead, was brutally tortured and murdered.”

Grayson's crimes "were heinous, unimaginable, without an ounce of regard for human life and just unexplainably mean. An execution by nitrogen hypoxia (bears) no comparison to the death and dismemberment Ms. DeBlieux experienced,” she added.

Grayson was the only one of the four teenagers who faced a death sentence since the other teens were under 18 at the time of the killing. Grayson was 19.

The execution was carried out hours after the U.S. Supreme Court turned down Grayson’s request for a stay. His final appeals had focused on a call for more scrutiny of the nitrogen gas method. His lawyers argued the execution method causes “conscious suffocation” and that the first two nitrogen executions did not result in swift unconsciousness and death as the state had promised.

Hamm said he thought some of Grayson's initial movements were “all show” but maintained other movements exhibited by Grayson and the two others executed by nitrogen gas were expected involuntary movements, including the breathing at the end.

No state other than Alabama has used nitrogen hypoxia to carry out a death sentence. In 2018, Alabama became the third state — along with Oklahoma and Mississippi — to authorize the use of nitrogen gas to execute prisoners.