The sixth search for the body of the IRA victim Columba McVeigh ended in failure, his family have said.
The 19-year-old man, from Donaghmore in County Tyrone, was kidnapped in 1975.
McVeigh was a victim of the ‘Disappeared,’ 16 people who were abducted, murdered and secretly buried by republicans during the Troubles. So far nine bodies have been recovered.
The IRA claimed he was an informer, a claim vehemently denied by his family, especially his mother Vera, who died in May 2007, aged 82.
The latest attempt to find his body began on 17 September in Bragan Bog, County Monaghan.
His family say they were "devastated" over the fruitless search, the BBC reports.
His brother, Oliver McVeigh, said that the Independent Commission for the Location of Victims' Remains (ICLVR) was doing everything in its power, but they needed more details.
"There are people out there who have the information and they haven't come forward and I can't understand why," he said.
"They have nothing to gain by keeping their secret and nothing to lose by telling the commission what they know. They know the information is confidential. Why do they continue to torture a family like this?"
Columba's sister Dympna said: "Our mother went to her grave unable to tend the grave of her son.
"If the people who know where Columba is buried could have seen what that did to my mother, if they could imagine their own mother in that position they could not stay silent if they had any human feelings at all.
"Let us bring Columba home and end this torment."
In response to the IRA Disappeared, the British and Irish governments established the ICLVR in an effort to gain confidential information about the location of their bodies.