The families of the two RUC officers whose deaths are being probed by the Smithwick Tribunal have called for new intelligence reports to be investigated by police on both sides of the border.
Chief Supt Harry Breen and Supt Bob Buchanan died in an IRA ambush just minutes after leaving a meeting in Dundalk Garda Station in March 1989.
Claims that a garda passed information to the IRA about that meeting are being examined by the Smithwick Tribunal.
Former garda sergeants Owen Corrigan, Leo Colton and Finbarr Hickey have all denied allegations of collusion.
During the week, new intelligence that the PSNI had obtained over the last number of years was finally presented to Judge Smithwick.
It claimed that a garda did pass information about the meeting involving the RUC officers to the IRA but that garda was not one of the three being examined by the tribunal.
This new intelligence also claimed that this ''fourth garda'' received a substantial amount of money from the IRA and passed intelligence to them for years.
Today the families of Supt Buchanan and Chief Supt Breen have demanded action following the revelation of this intelligence.
A spokesperson for Supt Buchanan's family, solicitor Ernie Waterworth, said the intelligence produced by the PSNI "confirms that collusion involving members of An Garda Síochána did exist".
He said that the Garda Commissioner should investigate the intelligence to identify any member or former member who may have colluded with the IRA.
The PSNI should also revisit the murders and examine all the available intelligence, he said.
The families also deserve an assurance that both police forces would provide each other with a full and open exchange of intelligence to bring the killers to justice, Mr Waterworth said.
The fact that this intelligence was held by the PSNI for several years and not revealed was "extremely hurtful" for the family of the RUC officer.
Mr Waterworth said they wanted to know if the information was held back at the request of the British security service, MI5.
Meanwhile, the spokesperson for Chief Supt Breen's family said that this new intelligence needed to be ''urgently probed and assessed".
