Alan Eugene Miller became the second death row inmate in the nation to be executed with nitrogen gas on Thursday evening, nearly 25 years after the shooting deaths of his three coworkers who he believed were spreading rumors about his sexuality.

Miller, 59, was convicted of murdering Terry Jarvis, Lee Holdbrooks and Christopher Yancy in two workplace shootings on the morning of Aug. 5, 1999, in the suburban Birmingham city of Pelham. He was officially pronounced dead at 6:38 p.m. CT, according to the Alabama Department of Corrections.

“I didn’t do anything to be here," Miller said before he was pronounced dead, reported the Montgomery Advertiser, part of the USA TODAY Network. Miller's next words were inaudible, but he seemed to have asked his family to take care of someone. Then: “I didn’t do anything to be on death row. Thank you."

Alabama Attorney General Steve Marshall said in a statement obtained by USA TODAY that "justice has been served."

"After two decades, Alan Miller was finally put to death for a depraved murder spree that cruelly took the lives of three innocent men," he said. "I ask the people of Alabama to join me in praying for the families and friends of the victims, that they might now find peace and closure."

Miller's death makes him the fourth inmate to be executed in Alabama this year, the 18th in the nation in 2024 and the 1,600th of all time in the U.S. He is also among five men being executed in the U.S. in just a six-day period: South Carolina executed Freddie Owens on Friday, and on Tuesday, Missouri executed Marcellus Williams less than an hour before Texas executed Travis James Mullis.

Miller previously survived the state's initial lethal injection attempt in September 2022, when staff could not find his veins for an IV line before his death warrant expired.

Alan Eugene Miller's final moments, meal

The execution began at 6:18 p.m. with gas flow, reported Marty Roney, who was among the witnesses in his role as a reporter with the Montgomery Advertiser, part of the USA TODAY Network. Miller gasped and struggled against restraints for about two minutes until he lost consciousness at 6:19 p.m. He gasped several more times and then appeared to take his last breath at 6:26 p.m., Roney said. The curtain to the chamber closed at 6:32 p.m.

On Wednesday, Miller had seven visitors and on Thursday he had nine, according to the Alabama corrections department.

Miller' last meal was of a hamburger steak, baked potato and French fries.

What was Alan Eugene Miller convicted of?

Miller was found guilty by an Alabama jury for shooting Holdbrooks six times, Jarvis five times and Yancy three times. He first shot and killed Holdbrooks and Yancy, his coworkers at Ferguson Enterprises, before driving his truck to Post Airgas, a welding supply store, to murder Jarvis.

Pelham police arrested Miller during a traffic stop on the same day of the murders. Once Miller was handcuffed, officers found a Glock lying on the driver's seat and an empty ammunition magazine on the passenger seat, according to court documents.

Despite Miller being deemed "mentally ill" by a forensic psychiatrist during his sentencing hearing, the court ordered him to be executed for the shootings, finding that his condition did not meet the level of mania necessary to establish an insanity defense under Alabama law.

"Miller suffered from a delusional disorder that substantially impaired his rational ability," according to the court document. "This delusional disorder − coupled with Miller's history as a loner − resulted in Miller's believing the people he worked with talked about him and that they had spread rumors about him. Miller believed that Terry Jarvis had told other employees at Post Airgas that Miller was a homosexual."

How was Alan Eugene Miller executed?

Miller was executed using nitrogen gas, the second time that method has been used in the U.S. after Kenneth Eugene Smith execution in January, which one witness described as "horrific."

The Rev. Jeff Hood, a spiritual advisor who has witnessed more than a half dozen executions, was at Smith's and described it as being "horrific" and bringing society closer to a "moral apocalypse."

"We're talking about minutes and minutes of thrashing and spitting," Hood told USA TODAY. "His head going up and down (and) back and forth. The (expletive) gurney that's bolted to the floor started shaking."

With nitrogen hypoxia is used, the inmate breathes pure nitrogen through a mask that displaces oxygen in their system. Proponents claim it is an almost instant and painless method. Opponents, including Hood, claim it is largely untried and torturous.

"Although the methods have changed over the years, it remains the judgment of the State of Alabama that some crimes are so horrific as to warrant the ultimate punishment," Attorney General Marshall said in his statement on Thursday. "In Alabama, we will not deny justice to the victims of heinous murders. Tonight, despite misinformation campaigns by political activists, out-of-state lawyers, and biased media, the State proved once again that nitrogen hypoxia is both humane and effective. Miller’s execution went as expected and without incident."

Who were Terry Jarvis, Lee Holdbrooks and Christopher Yancy?

Sherry Lawley called her brother, Terry Jarvis, the kindest and most generous person she knew.

"He would give you the shirt off of his back if he could," said Lawley, a resident of Maylene in central Alabama. "He would do anything for anybody … Terry was my baby brother, but at some point in life, it seemed like I became his baby sister because he took care of me."

After Jarvis was killed, she said: "It was just like a piece of my heart was missing that I won't ever get back."

Ahead of Miller's execution, she said she wasn't sure whether it would give her closure. "I know it needs to happen, and on one hand, I want it to happen, but I just don't know what to feel about it," she said.

Yancy was a faith-driven father of two and a "big teddy bear type," according to the Rev. Chris Joiner, the pastor of the Alabama church that he and his family attended.

"It was a strong family," Joiner told USA TODAY. "They were very loving and attentive to one another."

Yancy's family suffered another tragedy following his murder when his wife, Kim, was killed at the age of 38 in a car accident in 2012, according to the Shelby County Reporter.

USA TODAY could not reach Holdbrooks' family, but according to his obituary, he died a married man without any children.

Alan Eugene Miller's execution commenced despite attorneys' request

In March, Miller's attorneys filed for a preliminary injunction in federal court to stop the execution, arguing that it violated his rights to be free from cruel and unusual punishment.

"Alabama is evidently unable to carry out a nitrogen hypoxia execution without cruelly super-adding pain and disgrace, and prolonging death," a federal complaint filed by Miller's attorneys says.

Attorneys also said Miller was obese, had asthmatic bronchitis and received a diabetic food tray where was housed at Holman Correctional Facility, according to the complaint.

Miller's attorneys and the state entered into a confidential agreement in August, thus OK'ing the execution, according to court documents. A judge dismissed the attorneys' request without prejudice following the agreement.

Contributing: Marty Roney/ Montgomery Advertiser