John Rusnak was the most unlikely of rogue traders, writes Conor O'Clery, in Baltimore, Maryland. He was what his boss, Ms Susan Keating, called "a good, steady employee who had performed well over the years".
In his 30s, married and with two daughters, he lived quietly in a heavily-wooded suburb north of Baltimore.
He was an "upstanding member of the community and a member of the local school board", said Ms Keating, CEO and president of Allfirst, AIB's American subsidiary. The family apparently kept to themselves, not mixing with the neighbours, who include two lawyers and the Baltimore commissioner of police.
Mr Chris O'Neill, a real-estate manager who lives across Dixon Road from the Rusnaks, said that in six years he hardly saw them, other than Mrs Rusnak walking their dog.
A telephone call to the house on Sunday afternoon from an Allfirst treasury official looking into his trades apparently persuaded the trader that the game was up. On Monday, he failed to make his daily 15-minute journey down Highway 83 to the Allfirst building on South Charles Street.
The FBI came looking for him on Tuesday.
It asked neighbours, including Mr O'Neill, if he knew where Mr Rusnak was. "But at 9 o'clock they said they had located him out of state," Mr O'Neill explained.
That Mr Rusnak had surfaced was confirmed last night by Mr David Irwin, a criminal defence attorney for white-collar crime who was contacted by Mr Rusnak on Tuesday.
The lawyer, whose firm representated Linda Tripp in the Monica Lewinsky scandal, said that the FBI knew where he was and that he was not a fugitive. He hoped all would be "explained and sorted out in due course".
"If they're claiming that he stole money, that won't pan out. I'd be surprised if they ever came up with evidence that he stole money," Mr Irwin added.
Neighbours and colleagues were, however, unable to help solve the riddle of Mr Rusnak, a US citizen from Pennsylvania who joined Allfirst in 1993 and earned a reputation for steadiness.
A police car was parked yesterday in the drive of the rambling three-storey house set on a half-acre of wooded land, and a police officer threatened to arrest for trespassing anyone who approached the front door, as the family had complained about their privacy being disturbed.
The house would be worth about $300,000, said Mr O'Neill, affordable on Mr Rusnak's reputed salary of $85,000 plus bonuses.
"He has never given any reason for anyone to believe, in his performance and his job up until now, that he was an unusual individual in any way," said AIB's chief executive, Mr Michael Buckley. "We don't know whether he got away with anything. It's conceivable he got away with something, it's possible he had accomplices who got away with something."