Nebraska uses fentanyl for first time in execution

This Nebraska Department of Correctional Services photo shows death row inmate Carey Dean Moore. (AP)

Nebraska’s first execution since 1997 was carried out on Tuesday, in this case using a type of lethal injection never before administered in the state.

Carey Dean Moore, 60, was pronounced dead at 10:47 a.m. after being injected with a drug combination that included the powerful opioid fentanyl.

Moore was the first inmate to be lethally injected in Nebraska, which carried out its last execution in 1997 using the electric chair.

He was convicted in 1979 for the murder of two cabdrivers in Omaha.

In his final written statement, he admitted his guilt but said that there are others on Nebraska's death row who he believes are innocent and should be released.

Prosecutors said that at the age of 21, Moore fatally shot Reuel Van Ness during a robbery with his younger brother, using the money to buy drugs and pornography.

Moore fatally shot Maynard Helgeland by himself five days later, saying he wanted to prove he could take a man's life by himself. Moore was arrested a week later. He was charged and convicted of first-degree murder, while his 14-year-old brother was convicted of second-degree murder.

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The Nebraska drug protocol called for an initial IV dose of diazepam, also known as Valium, to render the inmate unconscious, followed by the powerful synthetic opioid fentanyl, then cisatracurium besylate to induce paralysis and inhibit respiration and potassium chloride to stop the heart. After each injection, prison officials sent saline through the IV to flush out any residue and ensure that all the drugs had entered the inmate's system.

Moore's execution comes a little more than three years after Nebraska lawmakers abolished the death penalty, only to have it reinstated the following year through a citizen ballot drive partially financed by Gov. Pete Ricketts. The Republican governor, a wealthy former businessman, has said he was fulfilling the wishes of voters in the conservative state.

Nebraska's Office of the Attorney General called the execution a "somber event" which put an end to "what has been a lengthy enactment of justice."

"Our sympathy is extended to the families of Reuel Van Ness and Maynard Helgeland for the loss of their loved ones nearly thirty-nine years ago," the statement read.

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A German drug company attempted to halt the execution last week, alleging that the state had illegally obtained on the company’s drugs and that proceeding with the execution would harm the firm's reputation and business relationships.

U.S. District Judge Richard Kopf ruled that blocking the execution would ‘frustrate the will of the people.”

Fox News' Bill Mears and The Associated Press contributed to this report.