Garda sources say they are "hopeful" but are aware of no further information that the IRA has relented and agreed to identify the burial sites of some of the people it kidnapped and murdered.
Responding to an Irish Times report that the IRA was preparing to disclose this information, the Sinn Fein president, Mr Gerry Adams, called on anyone with information about the "disappeared" to come forward and help families put the tragedy behind them.
"This is a very, very sensitive issue and I don't think it would be in anyone's interest to make any comment except what we have already said and that is our view that if people are missing, if they have been killed, that information should go to the families," he added.
A number of men are believed to have been murdered by IRA members from south Armagh and Tyrone and could well have been taken across the Border to be killed and secretly buried.
Among those believed to have "disappeared" in this fashion are Columba McVeigh, a 17-year-old youth from Dungannon who was abducted in 1977. No group ever claimed the abduction but local republican sources let it be known Mr McVeigh was suspected of being an informant and had been taken south of the Border, shot dead and then buried.
If this, indeed, was Columba McVeigh's fate, security sources feel it is probable he met his death somewhere in north Monaghan. Republican sources say the habit of secretly burying victims was dropped in the 1980s in favour of a policy of dumping the bodies north of the Border.
This was done because the location of the body decides in which jurisdiction the murder investigation takes place. Moving the body North meant i the Garda was largely removed from the murder investigations although the victims were killed inside the Republic. A number of men have gone missing from the Armagh area and are believed to have been kidnapped by the south Armagh IRA. These include Charles Armstrong (55), who was kidnapped on his way to Mass in Crossmaglen in 1981. His car was found abandoned nine days later in Dundalk. There was no sign of blood or a struggle. There was no official comment from the IRA about what happened to Mr Armstrong. However, local sources disclosed he had been kidnapped and killed, again because he was suspected of being an informant. His family have waited ever since for any news of what befell him.
Mr Gerald Anthony Evens, of Rathview Park, Crossmaglen, disappeared on March 27th, 1979, and was not heard of again. There was never any indication of what happened to him and no statement was ever issued by the IRA.
Mr Sean Murphy (25), of O'Neill's Estate, Creganduff, south Armagh, disappeared after leaving home to visit his girlfriend in Newry hospital. It is believed he was abducted by the IRA. Again there was evidence he was taken south of the Border. His car was recovered from Dundalk harbour some years later but with no sign of any remains. It is possible that these three men were killed somewhere in the Ravensdale Forest, a wood near the Border where the IRA was known to hide abducted people.
The Irish National Liberation Army (INLA) was responsible for killing one of its members and burying him in an unknown grave but this incident took place in Paris in 1985. The victim was Seamus Ruddy, formerly a leading figure in the organisation's political wing, the Irish Republican Socialist Party (IRSP).
One of the problems about Mr Ruddy's disappearance is that some of those who know where his body is buried were killed in INLA feuds. It is believed Mr Ruddy was beaten to death and buried, possibly in the Bois de Boulogne, on June 9th, 1985, after a dispute with other INLA members, one of whom was Peter Stewart from Belfast, who was killed in a feud in 1987.
Most of the other disappeared people are from Belfast and were killed during the 1970s and buried in the countryside above west Belfast. Some of the suspected sites of their graves have been built on since these disappearances.