A Dublin security tribunal today heard allegations that Sinn Fein's Martin McGuinness, Northern Ireland's deputy first minister, was involved in sanctioning the murders of two senior police officers in 1989.
The claim was made by "whistleblower" Ian Hurst, a former British army intelligence officer, who said Mr McGuinness had been head of the IRA's "northern command" when the officers were killed in an IRA border attack.
The accusations were rejected by Sinn Fein, a spokesman saying they were "more lies from an individual with a highly dubious track record."
The officers were ambushed and shot by an IRA gang just north of the border while returning from a meeting with police in the Irish Republic.
Hurst told the tribunal which is investigating the incident: "My understanding was that they were going to abduct them and interrogate them using extreme violence."
The tribunal is investigating allegations that a mole within the Irish police passed information to the IRA which led to the deaths. It has already heard various allegations of "rogue" officers within the southern force.
Sinn Fein said Hurst had no credibility, describing him as "part of a British security apparatus which played a very negative and malign role in the conflict."