Seamus Maguire, 29, from Aghagallon, near Lurgan, is believed to have been killed and secretly buried by republican paramilitaries in 1976.
A search to set to get under way later for one of the final four members of the Disappeared who remains missing.
Seamus Maguire, 29, from Aghagallon near Lurgan, is thought to have been killed and secretly buried by republican paramilitaries in 1976.
His name was added to those being searched for by the Independent Commission for the Location of Victims’ Remains (ICLVR) in 2022.
He remains missing, along with Co Tyrone teenager Columba McVeigh, former monk Joe Lynskey and soldier Robert Nairac.
The ICLVR said the search in Derryclone, Co Armagh, starting on Tuesday will be the first for Mr Maguire.
It is also the first search for one of the Disappeared in Northern Ireland since the remains of Peter Wilson were recovered from the beach at Waterfoot, Cushendall, in 2010.
ICLVR lead investigator Eamonn Henry said it had not been immediately clear whether Mr Maguire was a missing person case or the victim of an abduction, murder and secret burial by a paramilitary group.
“The criteria for a case to be accepted by the Commission are that the death and secret burial was as a result of paramilitary activity and was carried out before the signing of the Belfast/Good Friday Agreement on 10 April 1998,” he said.
“On the basis of information received from the PSNI, Seamus Maguire became one of the Disappeared in 2022.”
He said while they believe Republican paramilitaries were involved, it is not clear which wing of the IRA was responsible.
Mr Henry said Mr Maguire is thought to have been disappeared in 1976.
“It was initially thought that Seamus disappeared sometime around 1973-1974 but it was also subsequently suggested that after spending time in Manchester he may have returned to Northern Ireland and was then killed and secretly buried in the Aghagallon/Derryclone area in 1976 aged 29,” he said.
“Whatever the issues around specific dates, we are now satisfied that there is sufficient credible information to commence a search in the Derryclone area.
“The search area is around two acres in size and while unlike Bragan Bog where we searched for the remains of Columba McVeigh, regrettably without success, farmland is more stable each search site throws up its own challenges.”
He said the search will continue until they find what they are looking for or are satisfied that Mr Maguire is not there, adding: “I’m not going to put a specific timeframe on the search”.
Mr Henry also urged anyone with information about Mr Maguire’s disappearance to come forward.
“There may be an assumption that because a search is underway the Commission has all the information we need,” he said.
“That is not necessarily the case.
“If there is anyone who has any information on this case please get it to us.
“All information is treated in the strictest confidence and our sole purpose is to return the remains of a loved one to their family for a Christian burial.”
In a statement, Mr Maguire’s family described him as a “much loved eldest brother”.
“He has been missing now for over 50 years,” the family said.
“We hope that the Independent Commission for the Location of Victims’ Remains can now recover Seamus’s body so that he can be buried in St Patrick’s graveyard in Aghagallon with our parents May and Patrick.
“Our mum looked for Seamus right up until the day that she died.
“We appeal for privacy at this time. Our thanks to the ICLVR and all those involved in the search process.”
Northern Ireland Secretary of State Hilary Benn said: “My thoughts are first and foremost with the Maguire family, who have endured so many years of anguish since the abduction and disappearance of Seamus.
“I am deeply grateful to the commission for their unceasing efforts to find the Disappeared and for their painstaking efforts to help ease these families’ long-suffering.
“As well as the Maguire family, the families of Columba McVeigh, Joseph Lynskey and Robert Nairac still await the return of their loved ones’ remains.
“I urge anyone with information – no matter how insignificant they think it may be – to come forward and speak to the commission. All information will be treated in the strictest confidence.”
Anyone with information on the case of Mr Maguire or the other three outstanding Disappeared cases, Joe Lynskey, Columba McVeigh, Robert Nairac, should contact the ICLVR on +353 1 602 8655 or Secretary@iclvr.ie or ICLVR PO Box 10827 Dublin, Ireland.
