Fresh searches for one of the so-called 'Disappeared' victims have begun in Co Meath.
Brendan Megraw was abducted from his home in west Belfast in 1978.
The Independent Commission for the Location of Victims' Remains says a "geophysical survey" is focusing on a bog in Oristown near Kells.
The commission has carried out searches in this area before, the most recent in 2010, but now fresh information has come to light.
Over the next few days, specialist forensic investigators will carry out a ground-penetrating radar examination to map a five-acre area not previously analysed.
Mr Megraw was 23 when he was abducted from Twinbrook in Belfast in 1978 and murdered by the IRA.
His family have welcomed the new information but have said they are wary of getting their hopes up.
His brother Kieran acknowledged it would be a "difficult day" for the family.
"There is hope but the other side of the coin is you have to hold back your emotions as well," he said.
"The previous searches were three or four years ago and at that stage you wondered what the next step would be, but thankfully something has come in to the commission that they feel warrants some actions, which is good to hear."
He added: "We are obviously grateful for whoever has put forward the information. We have been making appeals, like the other families [of the Disappeared] have been making appeals, so it is good to know that some information is coming in."
Geoff Knupfer from the ICLVR said: "No one, least of all Brendan's family, is under any illusion that this is anything other than a huge task.
"But, with the right information, we are confident that we can find Brendan," he added.