Relatives of Colum Marks ended a High Court action after being told the Police Ombudsman is to launch an investigation amid claims of a ‘shoot-to-kill’ policy a by specialist RUC undercover unit.

It is believed the decision to launch a fresh watchdog probe follows the emergence of a new eye-witness.

Marks – a member of the IRA’s lethal South Down unit, was fatally wounded when police opened fire during an attempted mortar attack on security forces in Downpatrick, Co Down in April 1991.

The family and legal representatives of the 29-year-old claimed the RUC had an advance eight hours warning that the IRA operation was going ahead.

They argue that the police should have been able to arrest Marks given such intelligence.

Legal action was taken in a bid to compel the Police Ombudsman to investigate the shooting.

At a previous hearing, counsel for the family claimed there was material to suggest a state agent was involved.

They were seeking to judicially review regulations governing the watchdog which preventing it from probing a case where there has already been a police investigation.

But in court today, a lawyer for the Marks family confirmed the challenge was no longer necessary due to the Ombudsman’s decision to investigate.

Marks was part of an IRA team which was trying to murder members of the security forces with a deadly horizontal mortar in St Patrick’s Avenue on April 10, 1991, when they were surprised by the police officers.

As Marks fled in the dark into Dunleath Park, Downpatrick,  he was shot three times by a sergeant from the RUC’s elite Headquarters Mobile Support Unit.

He was alive long enough to reach the Downe Hospital but died during emergency surgery. The other IRA man escaped by running down St Patrick’s Drive and into the back door of a pub.

Last month, Northern Ireland’s Attorney General, John Larkin, announced he has written to the Director of Public Prosecutions asking for a review of a previous decision not to prosecute any of the police officers involved in the shooting.

At an inquest into Marks’ death the officers involved said shots were fired only after a warning was shouted, and that two warning shots were fired in the air.

However, the sergeant who fired the shots did not give evidence in person at the inquest while three others testified from behind screens.

The inquest also heard that the horizontal mortar, which was found on the driveway of a house which is now the Doris Pharmacy Plus chemist’s shop, had been triggered but the command wire had malfunctioned.

The jury found that Marks was an “active terrorist and a known member of the Provisional IRA.”

A former member of the INLA in the Newry area, the IRA described Marks as its commanding officer in the Downpatrick area.

After the shooting the then South Down MP, Eddie McGrady, of the SDLP, strongly supported the police actions saying it was clear Marks had been planning a major terrorist atrocity.

News of the Attorney General’s decision comes as the Marks family prepares to seek a judicial review into case and the RUC’s handling of the investigation.

However, the Attorney General’s request has been severely criticised by the TUV’s South Down Assembly election candidate Henry Reilly. He expressed “disappointment” the PPS has been asked to review the decision not to prosecute police officers.

Mr Reilly declared: “Let’s state some facts. Marks was a terrorist who was shot during an attempted mortar bomb attack.

“A primed mortar bomb was found near his body. It had been triggered and had only failed to go off because the command wire had malfunctioned.

“The IRA themselves described Marks as their officer commanding in the Downpatrick area.

“He had no thought for the lives of police officers when he went out with that bomb,” continued Mr Reilly.

“He went out with the intent of causing as much death and destruction as possible.Yet now the decision not to prosecute RUC officers for his death is being reviewed. What madness.”

Mr Reilly asked if anyone seriously believes that French security personnel who “thankfully took out” Islamic terrorists in the aftermath of the Paris attacks should be brought before the courts.

He added: “This news will be particularly insulting and distressing to innocent victims of the IRA who see members of that organisation elevated to the heart of government, while those who held the line against terror face the prospect of being dragged before the courts.”