The family of a man murdered over 40 years ago in Co Louth has announced that an independent investigation will be carried out into his killing by a former British police chief constable.

Seamus Ludlow was last seen alive in the Lisdoo Arms in Dundalk, Co Louth, in May 1976. 

The 47-year-old forestry worker's body was found with bullet holes in a ditch near his home on the Cooley Peninsula, Co Louth.

His relatives have said there will be a full independent investigation into his murder.

His family have argued for decades that he was an innocent victim of members of the British Army and loyalist paramilitaries who mistook him for a senior member of the IRA. 

They also believe gardaí were complicit in spreading false rumours that he was killed for being an IRA informant.

They have announced that former Bedfordshire Chief Constable Jon Boutcher will lead a full independent investigation into the murder in Northern Ireland and the Republic.

Mr Boutcher has been involved in a number of high-profile investigations relating to the Troubles, including leading Operation Kenova, which was set up to probe the activities of the British agent known as Stakeknife.

During a press conference held at the Lisdoo Bar in Dundalk, family solicitor Gavin Booth revealed that a witness came forward two weeks ago with new "significant information".

He appealed to anyone else with any information to come forward and help with this new investigation which is expected to last between two and three years.

Mr Booth described Seamus as "a quiet man. He was a family man and occasionally visited pubs in Dundalk and was known for his charitable work here".

"He was not political and was not interested in the conflict in the North and worked full time and was a devoted family man," he said.

Joined by members of Mr Ludlow's family, Mr Booth said the investigation will include cooperation of both the Police Service of Northern Ireland and An Garda Síochána.

"This investigation will be headed by Jon Boutcher who will look at the actions of all those who played a part in the role of the murder of Seamus Ludlow."

He said: "This includes the gardaí, the British army, the SAS, the RUC and any unknown others, including those suspects that were let go."

The investigation will form part of Mr Boutcher's independent review into a series of crimes linked to a terrorist group referred to as "The Glenanne Gang".

The Glenanne Series included a significant number of murders and other terrorist offences committed in both Northern Ireland and the Republic of Ireland during the Troubles between 1972 and 1978.

In a statement this evening, An Garda Síochána said it will work closely and in full cooperation with the review of the investigation into the murder of Seamus Ludlow under the auspices of Operation Kenova.