The landmark lawsuit, being taken against five men said to be responsible for the worst atrocity of the Northern Ireland conflict, heard the address of the school in Ballyshannon was given to an FBI agent who infiltrated the Real IRA.

The Dublin hearing was told David Rupert passed the evidence on to gardai who were probing terrorist activity on both sides of the boarder.

Michael McKevitt, the alleged leader of the RIRA, Liam Campbell, said to be his number two, Colm Murphy, Seamus McKenna and Seamus Daly all deny any involvement in the bomb attack in the Co Tyrone town on a busy Saturday afternoon in August 1998.

Superintendent Diarmuid O'Sullivan said five statements were taken from Rupert who, on January 20, 2001, in Chicago, handed over a brown envelope containing a number of documents.

The items included a business card which he said he was given from veteran republican Joe O'Neill. It allegedly had "Kathleen Askin, Vocational School, College Street, Ballyshannon" handwritten on the top. Ms Askin was Mr O'Neill's sister and a teacher at the school.

"This was the address that David Rupert was given by Joe O'Neill to ship military supplies from the US for the Continuity IRA," said Supt O'Sullivan.

Rupert also handed officers a piece of paper with the name and address of a man in Worcester, Massachusetts.

"David Rupert indicated that this was the person that Michael McKevitt instructed him to meet in the US to conduct his affairs," the detective told the court.

The envelope also included the name of a man who would act as a go-between for a journalist in Chicago and McKevitt.