But two “black holes” are hampering his private investigation, relatives of Mr Ludlow heard during their one and a half hour “progress” meeting with Judge Barron in Dundalk yesterday.

The “black holes” refer to the 28-year gap since the shooting and a possible political cover-up in 1979 after gardaí got key information on the killers’ identities.

No one was ever charged in connection with the Ludlow killing. A forestry worker from Mountpleasant, Dundalk, Séamus Ludlow, aged 47, disappeared on his way home from a pub in the town on the night of May 1/2, 1976.

At the time he was a well-known member of Fine Gael, the major party in the Liam Cosgrave-led government.