Any telephone numbers of suspects should have been provided to his inquiry, former detective chief superintendent Norman Baxter added.
29 people, including a woman expecting twins, were killed when a Real IRA car bomb exploded in the town 11 years ago.
Mr Baxter said: 'Omagh can't be seen as an individual incident, Omagh was the last in a series of incidents dating into the middle of the 1990s, the middle of 1997, and so there's a long lead-in to the Omagh explosion.'
He added: 'The information sits behind the intelligence which may have been of value in the early days of the inquiry.'
Intelligence Services Commissioner Sir Peter Gibson has said information on the bombers was shared with police following his review ordered by the British Prime Minister, but could not have stopped the attack in August 1998.
But Mr Baxter told the Northern Ireland Affairs Committee of MPs at Westminster that his terms of reference were 'far away' from the inquiry which Gordon Brown announced following claims that vital intelligence was deliberately held back.
'The expectations of the families who are still seeking closure were raised to a point that Sir Peter couldn't meet,' he added.
