Terry Nichols, an accomplice in the 1995 Oklahoma bombing has been sentenced to life imprisonment twice - and escaped the death penalty twice. BBC News Online explains the legal ins and outs of a complicated case.
Nichols did not testify during all the years of trials
US law bans a person from being tried twice for the same crime. Why was Nichols an exception?
He has been tried at two different levels - the federal and state. He was first convicted in a federal (national) court over the deaths of eight federal law enforcement officers killed when Timothy McVeigh bombed a federal building in Oklahoma City on 19 April 1995.
The federal court found him guilty in 1998 of conspiracy and involuntary manslaughter and sentenced him to life without parole.
He was then tried separately by an Oklahoma court in connection with the deaths of the other 160 people who died in the bombing, plus a foetus being carried by one of the victims.
He was convicted of 161 counts of first-degree murder and sentenced to life with no possibility of parole.
Don't these crimes carry the death penalty in the US?
They can, but neither jury was able to reach a unanimous decision that he should be executed - so under Oklahoma law, judges could not sentence him to death.
Timothy McVeigh, who was convicted of setting off the blast, was executed in 2001.
What does Nichols say about the explosion?
He remained tight-lipped through the years of trials. He did not testify in either the federal or state cases, and did not make a statement at the conclusion of the federal trial.
But after his sentencing in the state trial, he expressed remorse in a statement he read to the court.
"My heart truly goes out to all the victims and survivors and to everyone who was affected by the Oklahoma City bombing," he said.
"Words cannot adequately express the sorrow I have felt over the years for the grief they have all suffered."
What did the two sides say about him?
Prosecutors argued that Nichols had financed the blast and obtained key components of the bomb. "He contributed more than Timothy McVeigh," said prosecutor Lou Keel. "It was him, he had the money."
Defence lawyers alleged that McVeigh had set up Nichols to take the blame for the parts played by other unknown co-conspirators.
Can he appeal against the state's sentence?
He can, but his defence has reportedly urged him not to. If he fights the sentence and wins a new trial, prosecutors can again seek the death penalty. If he accepts his sentence, he cannot be executed.
He has 10 days to lodge an appeal following the sentencing.