MONTGOMERY — Attorney General Steve Marshall spoke Friday morning on Thursday evening's execution of Kenneth Eugene Smith, which was the first-ever execution in the state carried out by nitrogen hypoxia.

Smith was one of two men convicted in the 1988 murder-for-hire of Elizabeth Sennett. Sennett died after being stabbed eight times in the chest and once on each side of the neck.

SEE: Alabama executes convicted murderer Kenneth Eugene Smith; First death by nitrogen hypoxia in the U.S.

Marshall began by offering his condolences to Sennett's surviving family members, praising their "remarkable humility and grace" when speaking to the media shortly after Smith's execution.

"Let me start by saying what you've heard me say many times before, and this is I can hardly call this execution justice for the Sennet family," Marshall said. "And it's because it took over three-and-a-half decades for the sentence to be carried out. I want to tell the family, especially the victim's sons, Mike and Chuck, how genuinely sorry I am for the horrific manner in which their mother lost her life. But I also want to apologize today for how long it took for this sentence to be carried out."

Marshall also thanked the Alabama Department of Corrections and ADOC Commissioner John Hamm for being the first team in the country to carry out the "textbook" execution.

"They deserve a great deal of thanks and credit for being willing to be the one to step up, first in the country to do so, and I now suspect that many states will follow," Marshall said. "As of last night, nitrogen hypoxia as a means of execution is no longer an untested method; it is a proven one. It's the method that Kenny Smith ultimately chose, along with now 43 other death row inmates in our state."

"To my colleagues across the country, many of which were watching last night: Alabama has done it, and now so can you. And we stand ready to assist you in implementing this method in your states," he added.

Witnesses to the execution said Smith shook and convulsed on the gurney during the process, which reportedly took 22 minutes. Marshall said the "involuntary movements" were "perfectly consistent" with his office's filings and the filings submitted by Smith's lawyers.

Throughout the press conference, Marshall emphasized the need to remember the victim and hammered home his desire to see judgments like this move more swiftly.

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

"The majority of the questions that we've had here today have dealt with Mr. Smith," Marshall said. "We cannot lose sight of the fact that a woman was brutally murdered, taken from her family. And that's the reason the state of Alabama had to act last night. Let's remember her legacy and her life as much as we remember the person who took her away from us."

He continued, "It is my hope that one day, sooner rather than later, that the Alabama attorney general won't have to stand up here and talk about how many decades some families had to wait before justice was served."

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