The first federal execution in the United States for more than 17 years is set to go ahead in Indiana on Monday following a ruling by an appeal court.

The execution of convicted murderer Daniel Lewis Lee had been blocked on Friday by a federal judge.

This came after relatives of the victims sought a delay, saying they feared attending in person could expose them to coronavirus.

But the government appealed and the injunction was overturned.

The 7th US Circuit Court of Appeal said no federal statute or regulation gave the victims the right to attend the execution.

The relatives are going to appeal to the Supreme Court.

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Lee, a one-time white supremacist who tortured and killed a family of three before dumping their bodies in a lake, had originally been scheduled for execution in December. His case was delayed after the courts blocked the death sentence from being carried out.

Earlene Peterson, whose daughter, granddaughter and son-in-law were killed by Lee, has opposed the execution by lethal injection.

"It would shame my daughter," she told CNN last year, "that someone has to die for her."

Lee's planned execution is one of four that had been scheduled for July and August. All four men are convicted of killing children.

Federal and state executions - what's the difference?

Under the US justice system, crimes can be tried either in federal courts - at a national level - or state courts, at a regional level.

Certain crimes, such as counterfeiting currency or mail theft, are automatically tried at a federal level, as are cases in which the United States is a party or those which involve constitutional violations. Others are tried in federal courts based on the severity of the crimes.

The death penalty was outlawed at state and federal level by a 1972 Supreme Court decision that cancelled all existing death penalty statutes.

A 1976 Supreme Court decision reinstated the death penalty to a number of states and in 1988 the government passed legislation that made the death penalty available again at a federal level.

According to data collected by the Death Penalty Information Center, 78 people were sentenced to death in federal cases between 1988 and 2018 but only three have since been executed. There are 62 inmates currently on federal death row.

BBC