IRA sniper Bernard McGinn, pictured here on his release from prison (centre), has been found dead in a house in the Irish Republic

A man who confessed to his part in the murder of the last British soldier to die before the Good Friday peace agreement has been found dead.

Lance Bombardier Stephen Restorick was shot dead in South Armagh in February 1997. He had been talking and smiling with a Catholic woman when he was gunned down.

Bernard McGinn, aged in his 50s,was sentenced to life imprisonment for murder after telling investigators of his involvement in the killing, but that was overturned after an appeal court held that he had not been properly cautioned by police before making his confession.

He told detectives he rode "shotgun" in the car during the sniper attack, according to a transcript of the appeal judgement. Michael Caraher was the man who shot the soldier with the large rifle. Convictions for possessing guns and conspiracy to murder were upheld.

McGinn's body was discovered today at a house in Monaghan Town in the Republic.

A Garda spokesman said: "A man in his 50s was found dead in his house in Monaghan Town at 2pm this afternoon."

A post-mortem examination is expected to be held.

In 1999 McGinn was given three life sentences for the murder of L/Bdr Restorick, shot in the back with a powerful weapon at an army checkpoint in Bessbrook.

The village is in a border area close to the Republic which was notorious for IRA attacks, where troops were often helicoptered around because it was too dangerous for them to go by road.

As L/Bdr Restorick was speaking to a local woman, Lorraine McElroy, who was passing the checkpoint, he was hit by a bullet fired from a Barrett Light 50 rifle, a high-powered US weapon used to kill nine soldiers and police officers in Northern Ireland.

McGinn was also sentenced to a total of 490 years for a catalogue of terrorist offences including making the bombs destined for Canary Wharf, the Baltic Exchange and Hammersmith Bridge in London.

Under the terms of the Good Friday Agreement, he was released months after his conviction - he laughed at his sentences as he was led to the cells following the guilty verdict .

McGinn was also found guilty of murdering two other British soldiers. They were Lance Bombardier Paul Garrett in South Armagh in 1993 and former Ulster Defence Regiment soldier Thomas Johnston in 1978.

McGinn admitted to police that he made explosives north and south of the border on an almost daily basis: "like a day's work".

He and three other men were also found guilty of conspiring to murder a person or persons unknown in April 1997.

In September 2000 senior judges in Belfast held that the convictions on which McGinn was jailed for life, murdering the three soldiers, be quashed as he was not properly cautioned before confessing.

A transcript of the appeal judgment said: "We are of the view that it is at least possible that McGinn believed that the admissions that he volunteered to his interviewers would not be used against him.

"We also consider that there is a reasonable doubt as to whether he would have made those admissions if, as soon as he embarked upon them, he was cautioned in respect of them and the provisions in relation to the conduct of interviews were observed."

The court dismissed appeals against convictions for possessing guns and conspiracy to murder, for which he was jailed for 20 years.

The continuing threat from dissident republicans established in opposition to the peace process was illustrated in March 2009 when two soldiers, army engineers Mark Quinsey and Patrick Azimkar, were killed in what a judge described as a "ferocious and ruthless" gun attack outside Massereene barracks in Antrim Town.