Alabama is officially the first state to put an inmate to death by nitrogen hypoxia.

Kenneth Eugene Smith, 58, was pronounced dead at 8:25 p.m. Smith was one of three men convicted in the 1988 murder-for-hire plot of Elizabeth Sennett.

“On March 18, 1988, 45-year-old Elizabeth Sennett’s life was brutally taken from her by Kenneth Eugene Smith," Governor Kay Ivey said in a statement. "After more than 30 years and attempt after attempt to game the system, Mr. Smith has answered for his horrendous crimes."

“The execution was lawfully carried out by nitrogen hypoxia, the method previously requested by Mr. Smith as an alternative to lethal injection," she continued. "At long last, Mr. Smith got what he asked for, and this case can finally be put to rest."

“I pray that Elizabeth Sennett’s family can receive closure after all these years dealing with that great loss.”

Reporter witnesses said the execution took about 22 minutes and he shook on the gurney before he died.

Smith's final statement was, “Tonight Alabama causes humanity to take a step backwards. ... I’m leaving with love, peace and light.”

He made the “I love you sign” with his hands toward family members who were witnesses. “Thank you for supporting me. Love, love all of you,” Smith said.

The nitrogen hypoxia method has been authorized for executions in Alabama, Oklahoma and Mississippi, but until Thursday, no other state had used it.

The protocol includes a full facepiece being placed on the inmate’s face, forcing them to breathe in oxygen-deficient air with nitrogen. The nitrogen is administered until an EKG shows a flatline for five minutes.

While the state maintains nitrogen hypoxia is painless, those who oppose the death penalty argue it is cruel and unusual punishment.

"Justice has been served," Alabama Attorney General Steve Marshall said following the execution. "Tonight, Kenneth Smith was put to death for the heinous act he committed over 35 years ago: the murder-for-hire slaying of Elizabeth Sennett, an innocent woman who was by all accounts a godly wife, a loving mother and grandmother, and a beloved pillar of her community."

"I ask the people of Alabama to join me in praying for Elizabeth’s family and friends, that they might now better be able to find long-awaited peace and closure," Marshall continued."

In a statement before the execution, Smith and the Rev. Jeff Hood said, “The eyes of the world are on this impending moral apocalypse. Our prayer is that people will not turn their heads. We simply cannot normalize the suffocation of each other.”

Nitrogen hypoxia is the first new method of execution added in Alabama since the early 1980s when lethal injection was added.

Smith and John Parker stabbed and beat Sennett to death at her home.

"They stabbed her, I forget how many times, 10 or 15 times, in the neck and head," Charles Sennett, the victim's son told 1819 News. "She had scars all over her upper body. Me and my brother went out there to the farm and had to have the carpet replaced, we cleaned the walls, the fireplace, everything. It was just bad. It was bad. And so, she apparently had put up a good fight. It was terrible. It was terrible."

The two had been recruited by Billy Williams, who prosecutors said was hired by the victim’s husband, Charles. Charles Sennett, a pastor, killed himself before he could be charged. Parker was put to death by lethal injection in 2010, and Williams, who was sentenced to life in prison, died behind bars.

Smith’s attorneys have fought his death sentence for years, leaving the Sennett family in a prolonged state of despair.

RELATED: 'Alabama’s judicial system sucks': Son of murder victim wants justice to be served

The state failed to execute Smith by lethal injection in 2022 when they couldn’t administer an IV due to him being severely dehydrated. The Sennett family believes Smith purposefully did not eat or drink to avoid execution.

Before his nitrogen hypoxia execution Thursday he was served a T-bone steak, hashbrowns, toast and eggs.

AG Marshall said the Thursday night execution was historic.

"Alabama has achieved something historic," he said in a statement. "Like most states, Alabama has made the judgment that some crimes are so horrific that they warrant the ultimate penalty. But anti-death-penalty activists have worked to nullify that moral judgment through pressure campaigns against anyone assisting states in the process."

"They don’t care that Alabama’s new method is humane and effective, because they know it is also easy to carry out," Marshall continued. "Despite the international effort by activists to undermine and disparage our state's justice system and to deny justice to the victims of heinous murders, our proven method offers a blueprint for other states and a warning to those who would contemplate shedding innocent blood. This is an important night for Liz Sennett’s family, for justice, and for the rule of law in our great nation."

To connect with the author of this story, or to comment, email erica.thomas@1819news.com.

Don’t miss out! Subscribe to our newsletter and get our top stories every weekday morning.