The indictments were returned under seal Monday, a law enforcement official with knowledge of the investigation told The Associated Press on Wednesday. The official spoke on condition of anonymity because the indictments had not been formally announced.
Marjorie Diehl-Armstrong, already imprisoned for killing her boyfriend, was notified Tuesday that she may face charges of bank robbery, conspiracy and a firearms count, lawyer Lawrence D'Ambrosio said. He says Diehl-Armstrong, 58, is innocent.
Federal authorities also notified a man described as Diehl-Armstrong's fishing companion, Kenneth E. Barnes, that he faces charges. Barnes, 53, is jailed on unrelated drug charges.
Still not known is whether deliveryman Brian Wells was part of the plot, reports CBS News correspondent Cynthia Bowers.
The U.S. attorney's office has declined to comment until a news conference later Wednesday to announce a "major development."
On Aug. 28, 2003, 46-year-old Brian Wells set out to deliver an order for two pizzas to a mysterious address that turned out to be the location of a TV tower. He turned up about an hour later and roughly two miles away at a PNC Bank branch in Summit Township, with a note demanding money and saying he had a bomb.
Wells took the money from a teller, got into his car and was soon captured by police. Hanging from his neck under his T-shirt was a triple-banded metal collar and a device with a locking mechanism that kept it in place. Attached to the collar was a bomb.
"It's going to go off," Wells said. "I'm not lying."
Someone had started a timer on the bomb, Wells said, and forced him to rob the bank.
While police waited for the bomb squad, the bomb exploded, killing Wells. Police found a gun resembling a cane in the car and a nine-page handwritten letter that included detailed instructions on what Wells was to do with the bank money and how he could unlock the collar by going through a kind of scavenger hunt, looking for clues and landmarks.
The note also included a list of rules and a threat that Wells would be "destroyed" if he failed to complete his mission.
Diehl-Armstrong, 58, has been linked to the Wells investigation because her boyfriend's body was found in the freezer of a home near the TV tower where Wells made his final delivery. She pleaded guilty but mentally ill to killing her boyfriend and is serving a sentence of seven to 20 years in state prison.
The man who owned the home, William Rothstein, was questioned in Wells' death but has since died of cancer.
Authorities have never said whether they believe Wells was an innocent victim, a conspirator or someone who knew something about the robbery plot but did not realize the risk he faced. Wells' family believes he was just a victim.
D'Ambrosio, Diehl-Armstrong's attorney, has said he believes she had nothing to do with Wells' death but may have known the people behind the robbery.