Daniel Lewis Lee, a convicted killer, was executed on Tuesday morning, July 14, in the first federal execution in 17 years after the Supreme Court reversed lower court ruling and ruled federal executions could proceed.

He received a lethal dose of the powerful sedative pentobarbital in Terre Haute, Indiana, 

According to a pool report, Lee was pronounced dead by the coroner at 8:07 a.m. ET in Terrre Haute, Indiana. His last words were "I didn't do it. I've made a lot of mistakes in my life but I'm not a murderer. You're killing an innocent man."

Lee, a one-time white supremacist was convicted in Arkansas of the 1996 killings of gun dealer William Mueller, his wife, Nancy, and her 8-year-old daughter, Sarah Powell, dumping their bodies in a lake.

Several executions were initially delayed when a judge ruled on Monday that there were still unresolved legal challenges. But the Supreme Court cleared the way for the resumption of the federal death penalty in an unsigned order released, wiping away a lower court order temporarily blocking the execution of Lee in a 5-4 vote as 5 conservative judges voted in favour while four voted against the execution.

The supreme court in an unsigned opinion said that the prisoners’ “executions may proceed as planned,” with Lee’s execution scheduled for about 4 a.m. EDT Tuesday, according to court papers.

Here are three more federal executions that are scheduled in the near future. 

• Wesley Ira Purkey, who was sentenced in Missouri in 2003 for the rape and murder of a 16-year-old girl whose body he dismembered, burnt and dumped in a septic pond, is due to be executed on Wednesday.

• Dustin Lee Honken, sentenced in Iowa in 2004 for shooting dead five people including two girls aged six and 10, is due to be executed on Friday.

• Keith Dwayne Nelson, sentenced in Missouri in 2001 for the rape and murder of a 10-year-old girl behind a church, is set to be executed next month.