A man who took part in a bizarre bank robbery plot that turned deadly when a bomb fixed to the neck of a pizza delivery man exploded has been sentenced to 45 years in a US federal prison.
Kenneth Barnes, 55, was "intimately involved" and not just a minor player in the plot, US District Judge Sean McLaughlin said on Wednesday.
Barnes had suggested bomb components, provided magazine articles about bomb making and was present when the pipe bomb was put on pizza delivery man Brian Wells, McLaughlin said.
Barnes apologised to Wells' family before the sentence was imposed.
"What happened to him was something that wasn't supposed to happen," he said.
Barnes had pleaded guilty in September to using a destructive device during a crime of violence and conspiracy to commit bank robbery. The prison term was beyond the 30-year mandatory minimum required by law.
Prosecutors concluded Wells was an active member in the scheme at first, but was coerced as the plot unfolded. When he realised the bomb was real, he refused to put it on and did so only after being threatened with a gun, prosecutors said.
Wells' family, however, continues to assert he was an innocent victim who had no role in planning the robbery.
The investigation into the convoluted scheme began when Wells, 46, walked into a PNC Bank branch on the outskirts of Erie, Pennsylvania, on August 28, 2003, with a pipe bomb locked onto his neck.
He presented a teller with a note demanding money and walked away with about $US8,700 ($A13,488).
Wells was cornered by police a short time later and told officers the bomb had been put on his neck at gunpoint. It exploded and killed him as officers waited for a bomb squad to arrive.
Lawyer Mary Beth Buchanan called Barnes' sentence "appropriate and just", noting that it was essentially a life term.
The plot's alleged mastermind, Marjorie Diehl-Armstrong, 59, is awaiting an examination to determine if she is mentally competent to stand trial.
Barnes has agreed to testify against her. Prosecutors said Diehl-Armstrong was angry with her father about an inheritance dispute and wanted to rob a bank to raise money to pay Barnes to kill him.
She is currently serving a seven to 20-year prison sentence for killing her boyfriend, 45-year-old James Roden, to keep him silent about the bank robbery scheme. She pleaded guilty but mentally ill in that case.
