The Police Ombudsman for Northern Ireland is launching a new investigation into the killing of Colum Marks by the Royal Ulster Constabulary (RUC) in Downpatrick twenty-five years ago.

Belfast firm KRW Law, which had been taking legal action to compel Police Ombudsman Michael Maguire to investigate the circumstances of the 1991 killing, said it had sent new information to the Ombudsman which precipitated the inquiry.

The family has always held the RUC had prior intelligence that the IRA were planning to launch a mortar attack on a police patrol and were lying in wait when the IRA unit - including Colum Marks - arrived.

Now KRW Law says an eyewitness has corroborated claims that Mr Marks was shot after having been arrested by RUC officers.

Solicitor Gavin Booth of KRW Law said: “The advance knowledge police had about the attack meant they should have been in a position to arrest him without opening fire.

“The police claimed Colum Marks ignored a number of warnings to stop and was shot because it was feared he posed a threat.

“No gun nor explosive residue was ever found on Colum Marks, supporting claims that he was shot after being arrested. An eyewitness has now come forward and supported these claims.”

According to Mr Booth, an eyewitness has claimed to have seen a man, believed to have been Colum Marks, being escorted along a street under police guard on the night of the shooting.

He said it was clear the man was under arrest, and that three RUC officers were with him.

Mr Booth said: “This new information fundamentally undermines the police account of what happened. It supports the family’s claim that Colum was shot after being arrested.

“This was clearly a shoot-to-kill operation. Serious questions remain unanswered around the murder of Colum Marks. This is another step forward in this process.

“Last month we welcomed the decision by the PPS to review the decision not to prosecute the officer who murdered Colum Marks.”