Published Wednesday, 27 August 2014
Brendan Megraw was abducted, killed and buried in an unknown location in April 1978.
He, and 16 other people also buried in unknown locations, have become known as the Disappeared and attempts have been made over the years to relocate their remains, reunite them with their families and give them a burial.
It is believed the remains of Mr Megraw lie in a bog in Oristown, Co Meath.
There have already been three searches of a 10 acre section of the land in the area, the most recent in 2010.
The new search is focusing on five acres of bogland that have not been examined previously.
Forensic archaeologists, using radar, are surveying the land to identify anomalies beneath the surface to determine if excavation work is necessary.
Mr Megraw's brother Kieran admitted it is a "difficult day" for the family.
He said: "There is hope but the other side of the coin is you have to hold back your emotions as well."
It is understood the latest bid to find the body comes after new information was received by the Independent Commission for the Location of Victims' Remains (ICLVR) - the body set up jointly by the British and Irish Governments to liaise with former paramilitaries to find the Disappeared.
Mr Megraw stressed the importance of anyone with information giving it to the commission.
He added: "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.
"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."
Mr Megraw, from Twinbrook, was looking forward to the birth of his first child and was due to start a new job on a ship when he went missing.
The IRA claimed he had confessed to being a British provocateur and Military Reaction Force undercover agent in 1978.
The ICVLR was established in 1999 after the Good Friday peace agreement and is acknowledged as a world leader in the search and recovery of human remains from bogland.
The remains of 10 of the Disappeared have been recovered but the bodies of seven others have yet to be found.
Anyone with information can contact the ICLVR on 00800 5558 5500.
© UTV News