A Commission of Investigation has found that a garda who shot dead a Real IRA man during an armed robbery 20 years ago believed his life was "in mortal danger" and used "proportionate and necessary" force.

Ronan MacLochlainn was killed as the gang tried to flee the scene in Ashford, Co Wickow on 1 May 1998, when gardaí foiled an armed raid on a security van.

The commission also said it was satisfied that Mr MacLochlainn had held a loaded gun to the head of an elderly man, and that he was pointing it at two gardaí when he was shot dead.

It found that it would have been extremely difficult for the State to have organised this operation in such a way as to avoid killing Mr MacLochlainn without danger to the gardaí or the general population.

However, the Chairperson of the Commission, Mary Rose Gearty, criticised the garda's subsequent management of the crime scene and described an assault by a garda on one of the other gang members as "deplorable".

The Chairperson also concluded that gardaí should have adapted and practiced more rigorous training for its senior management which would have encouraged recognition among its members for accountability and real independence in its own internal investigation.

These measures she said could have saved the MacLochlainn family, the civilian witnesses and the gardaí - particularly those who fired the shots - the long ordeal of such a distressing investigation so very long after the events.