A search for the body of one of the Disappeared in a plot of land in County Meath has ended without success.
Joe Lynskey was abducted and murdered by the IRA in 1972. The latest search for his remains started in March.
The Disappeared were 16 people abducted and secretly buried by republicans in the 1970s and 1980s.
So far, the remains of 13 people have been recovered. The remaining three are Mr Lynskey, Columba McVeigh and Robert Nairac.
During a previous search for Mr Lynskey at nearby Coghalstown in 2015, the remains of Kevin McKee and Seamus Wright were recovered.
Mr Lynskey's niece Maria Lynskey said that all families wanted was "to see all the remaining Disappeared returned".
"As for me all I can do is to hope and to pray," she said.
"Hope that there is someone out there who knows something and pray that they will have it in their heart to help us to bring Joe home for the Christian burial that he has been denied for nearly fifty years," she added.
Mr Lynskey was a former Cistercian monk, who later joined the IRA.
Jon Hill, senior investigator with the Independent Commission for the Location of Victims' Remains (ICLVR) said it was "deeply disappointing".
"The information we were working from was given in good faith and warranted further investigation.
"Unfortunately that has not produced the result that we all hoped for."
Mr Hill also issued an appeal for fresh information and made assurances that any information received would be "treated in the strictest confidence".
"There is a cast iron guarantee, enshrined in international legislation, that the information we receive and the identity of those providing it will never be revealed to anyone else," he said.