ERIE — A Pennsylvania woman fidgeted and whispered angry denials as a federal prosecutor told a jury that she played a role in a devious scheme to lock a bomb onto the neck of a pizza deliveryman and force him to rob a bank.

"That's a lie," Marjorie Diehl-Armstrong, 61, of Erie, hissed into her attorney's ear at one point. "Makes me sick."

Diehl-Armstrong's trial began Friday on armed bank robbery and other charges in the plot that killed 46-year-old Brian Wells. She faces a possible life sentence.

Diehl-Armstrong's trial marks the widest window yet into a bizarre plot that captivated northwestern Pennsylvania in the waning days of summer in 2003. The other people allegedly involved in the case are either dead or have pleaded guilty.

On Aug. 28, 2003, Wells walked into a bank with a bomb strapped to his neck and walked out with $8,702. He was stopped by police nearby and was sitting on the ground in handcuffs when the bomb went off, killing him, as officers waited for a bomb squad to arrive.

In 2007, when federal authorities announced charges against Diehl-Armstrong and her friend Kenneth Barnes, investigators revealed that they believed Wells was in on the plot.

Though prosecutors had previously asserted that Diehl-Armstrong hatched the scheme as a way to get $250,000 so she could hire a hit man to kill her 91-year-old father, Assistant U.S. Attorney Marshall Piccinini told jurors in his hour-long opening statement that Diehl-Armstrong was "not being charged with being the mastermind" and called her an "aider and abetter."

Prosecutors don't have to prove Diehl-Armstrong led the plot. They must only convince the jury she was part of it, was aware of the other participants, knew their goals and actions and furthered the plot.

Piccinini said she did those all things. He said she provided two egg timers another plotter used to build the bomb. She also told a fellow inmate she was there when Wells' neck was measured for the bomb collar, Piccinini said.