A pizza delivery man killed by a bomb around his neck after apparently being forced to rob a bank was a conspirator, not a hostage, US authorities say.
Brian Wells's family say they do not believe he was part of the plot
Brian Wells, 46, died when the device exploded after police surrounded him after he left the bank in Summit Township, Pennsylvania, in 2003.
A US grand jury has indicted two people in connection with the plot, both of whom are in jail for unrelated crimes.
The dead man's brother has rejected claims that Wells was part of the plot.
John Wells said he could not believe the police expected the public to believe that his brother would willingly have put on the timer-controlled bomb.
Just before he died, Wells told police he had been forced into the robbery by gunmen.
Speaking at a news conference, US Attorney Mary Beth Buchanan said it had taken the authorities almost four years to complete an "extremely challenging and complex investigation".
According to the indictment, Marjorie Diehl-Armstrong, 58, and Kenneth E Barnes, 53, are charged with bank robbery and conspiracy. They are due in court later this week.
Diehl-Armstrong is already serving a sentence for killing her boyfriend, while Barnes is in jail on drug charges.
Marjorie Diehl-Armstrong is in prison for killing her boyfriend
Ms Buchanan said Wells had had a limited role in the plot but that he had been involved in the planning stages.
She said his motive was unclear and he may not have known that the bomb he carried was live.
"Sadly the plans of these other individuals were much more sinister... and he died as a result," she said.
"It may be that his role transitioned from that of the planning stages to being an unwilling participant in the scheme."
Investigators believe the reason for the live bomb was to ensure that Wells handed over the money after carrying out the robbery - and so that if he was caught, he could claim to have been forced into it.
The bizarre case unfolded in August 2003, when Wells, a pizza delivery man, was called to deliver two pizzas to an address in a remote area of Erie.
The bomb Brian Wells was wearing exploded before it could be defused
An hour later, he walked into the PNC Bank about two miles (3km) away with a note demanding money and saying he had a bomb.
Wells took the money and left the bank, but was soon cornered by police, who discovered he had a bomb round his neck, which was locked in place.
Wells said the device was on a timer, telling police: "It's going to go off. I'm not lying."
The bomb squad was called but the device exploded, killing him.
Ms Buchanan said investigators believed Diehl-Armstrong had killed her boyfriend to keep him from revealing the plot and that she intended to use the proceeds of the robbery to pay a hitman to kill her father.
Responding to Ms Buchanan's address, John Wells said he and his family were very angry at the claim that Brian Wells had been a co-conspirator.
"I don't want my brother being used," he said, accusing the authorities of failing to investigate the case properly.
"My brother was not involved in the bank robbery. He wasn't involved in the planning of the bank robbery."
He also criticised local police for having been too slow to call bomb squad officers to defuse the device.