White supremacist Daniel Lewis Lee was put to death on Tuesday morning (July 14) in the country’s first federal execution in 17 years. The 47-year-old man was killed by lethal injection at a federal prison in Terre Haute, Indiana, CBS reports.

In 1996, Lee and accomplice Chevie Kehoe killed an African American family of three in Arkansas in a plot to create a whites-only nation. The Oklahoma native was a confessed member of the white supremacist organization Aryan Peoples’ Republic. Lee was found guilty of multiple offenses, including the murders of William Mueller, his wife Nancy and her 8-year-old daughter Sarah Powell.

According to the Associated Press, his last words on Tuesday were, “You’re killing an innocent man.”

“I didn’t do it. I’ve made a lot of mistakes in my life but I’m not a murderer,” he reportedly said.

Lee’s execution occurred after the Supreme Court decided early on Tuesday (July 14) in a 5-4 ruling to move it forward. The ruling overturned a U.S. District Court judge’s executive order that put a hold on Lee’s execution on Monday (July 13).

Relatives of the victims’ family have previously expressed their opposition to Lee being put to death and instead said they wanted him to serve a life sentence in prison, like his co-defendant Kehoe. The relatives were also concerned that traveling to attend the execution would put them at a heightened risk of contracting Coronavirus.

“For us it is a matter of being there and saying, ‘This is not being done in our name; we do not want this,’” relative Monica Veillette told CBS.

Civil rights groups and anti-death penalty advocates also raised concerns over the timing of Lee’s execution amidst the pandemic. Two other federal executions are scheduled for this week.

“The government has been trying to plow forward with these executions despite many unanswered questions about the legality of its new execution protocol,” an attorney for one of the men facing execution, Shawn Nolan, said.

In 2014, a botched state execution in Oklahoma led President Barack Obama to order the Justice Department to conduct a broad review of its capital punishment system. Last July, the attorney general said that the review had been completed, allowing executions to resume.