An area in County Louth examined as part of an investigation into the disappearance of Army officer Robert Nairac “was never a grave site”, investigators have said.
The Independent Commission for the Location of Victims’ Remains (ICLVR) led Tuesday’s search.
It followed “strong indications” by specialist, cadaver dogs.
However, the lead investigator, Geoff Knupfer, said there was no evidence of disturbance to the site.
Robert Nairac was one of 16 people abducted and murdered by republicans during the Troubles.
His body has never been found and there has been much speculation about the disposal of his remains.
The ICLVR, which was set up to find the bodies of the Disappeared, said the archaeological examination in Ravensdale forest had been “careful and painstaking”.
Mr Knupfer said: “We were looking at quite a defined area at which the cadaver dogs had apparently given strong indications.
“If the subsurface had been disturbed by a spade or any other device or implement cutting into it to bury remains we would have seen clear evidence of that.
“There was none. The subsurface was pristine. It was never a grave site.”
So far, remains of 12 of the 16 who disappeared have been recovered.
The commission is also currently searching for Columba McVeigh in Bragan Bog, County Monaghan.
Mr McVeigh, 19, from Donaghmore, County Tyrone, was also killed and secretly buried by republicans after being kidnapped in November 1975.
Mr Knupfler said the commission made “careful judgments”.
“We work from credible information and draw on years of experience with some of the best forensic archaeologists in Ireland and the UK to narrow down a site and all we can ever say with confidence is that if the remains are there we will find them,” he said.
“In the last five years we have conducted four substantive searches and recovered the remains of four of The Disappeared.
“But there are no guarantees where bodies have been secretly buried over 40 years ago.”