The BBC Panorama television programme is to name suspects it claims were responsible for the "Real IRA's" Omagh bombing, in which 29 people died.
Individuals questioned by police about the 1998 bombing will be named on the programme on Monday, the BBC said.
The RUC and the Garda interviewed 87 people about the bomb but only one person has been charged in connection with the blast. Mr Colm Murphy is expected to go on trial in Dublin next year.
The BBC said it would name "several" people questioned. In the programme, reporter John Ware investigates the actions of a number of individuals. The BBC said: "Each has yet to explain their movements on the day of the bombing." It added: "In each case they have failed to answer detailed questions about their connection with mobile phones which were tracked into and out of Omagh on the day of the bombing."
The BBC is also claiming that the suspects failed to explain their alleged connection to telephones linked to other "Real IRA" bomb attacks. Panorama said it had uncovered documents and secretly filmed the suspects during a detailed investigation covering several months. Some were confronted at their homes.
RUC acting Assistant Chief Constable Mr Eric Anderson told the Omagh inquest earlier this week that police knew who was responsible for the bomb but did not have enough evidence.
Mr Tony Hall, BBC's head of news, said: "The decision to name the suspects is right."