The federal government carried out its first execution in 17 years early Tuesday when Daniel Lewis Lee, convicted in the 1996 slaying of an Arkansas family, was put to death by lethal injection at the U.S. Penitentiary in Terre Haute, Indiana.

Lee, a once-avowed white supremacist, was pronounced dead at 8:07 a.m., following a protracted legal fight that delayed his execution by more than 16 hours.

"You're killing an innocent man," Lee said before he died.

Lee's execution had been scheduled for 4 p.m. Monday, but a series of legal challenges delayed the sentence. A 5-4 Supreme Court decision in the early hours of the morning Tuesday ultimately cleared the way for Lee's lethal injection and the scheduled executions of three other inmates.

Lee's murder victims included an 8-year-old girl, her mother and the woman's husband. After robbing and shooting the victims with a stun gun, along with accomplice Chevie Kehoe, the killers covered the victims' heads with plastic bags, sealed the bags with duct tape, weighed down each victim with rocks, and threw the family of three into the Illinois Bayou in Arkansas.

Until the Supreme Court acted early Tuesday, the appeals court had denied the government's request to lift the stay ordered by U.S. District Judge Tanya Chutkan, who concluded that four inmates, including Lee, had not exhausted their challenges to the government's execution protocol which they claimed risked inflicting "severe pain."

The judge's ruling touched off a legal scramble that lasted deep into the night and early morning.

Chutkan said that the federal government's new method of lethal injection, using the single drug pentobarbital, had produced evidence of severe breathing problems. Chutkan went on to say that the condemned prisoners had identified other alternatives, including a multi-drug mixture or the rarely used firing squad.

Chutkan's ruling was followed by a flurry of Supreme Court filings in which the government and advocates for Lee and the other inmates continued their legal battle, even as Lee's scheduled 4 p.m. execution time lapsed without action.

"Hours before the first execution was set to take place, the District Court preliminarily enjoined all four executions on the ground that the use of pentobarbital likely constitutes cruel and unusual punishment prohibited by the Eighth Amendment," Supreme Court ruled Tuesday, adding that vacating the injunction is "appropriate" because the inmates' claim was not likely to succeed as it faced an "exceedingly high bar."

The filings raised a range of questions, from the threat posed by coronavirus to witnesses and continuing disputes related to the execution protocol to a claim that Lee's trial lawyers provided ineffective assistance.

Friday, an Indiana federal judge blocked Lee's execution, citing the threat posed by the resurgent coronavirus. U.S. District Judge Jane Magnus-Stinson acted on a legal challenge brought by family members of the victims who asserted that the pandemic posed an unreasonable health risk to them as prospective witnesses.