The appointment of a forensic expert, skilled in finding human remains, was suggested to the British and Irish governments more than three years ago, Sinn Féin president Gerry Adams has claimed.
Speaking in Dublin, he questioned why the governments had taken until now to follow up on his party's proposal. "I welcome that they have finally moved but there's a question mark as to why it took so long," he said.
An appointment of a forensic specialist, as promised by the Minister for Justice, Mr McDowell, is not expected for some weeks.
The appointee will help in the search for the so-called Disappeared, those abducted, killed and buried by the IRA during the Troubles. Mr Adams said he hoped those bodies still to be found would be located and returned to their families for burial.
"I'm fairly certain, without raising expectations, that we will eventually get those remains and give them back to the families," he said. "We have never stopped trying to help. I understand that this is a horrendously difficult issue, particularly for families who are being denied a funeral."
He made his remarks as the families of others who have gone missing, presumed dead, also called for such a government-appointed specialist to help investigate their cases.
Their appeals have been backed by a children's charity and political representatives. The National Society for the Prevention of Cruelty to Children's divisional director, Ian Elliott, said the cases of missing, presumed murdered, children should be further investigated. However, he admitted: "I have no sense of what the government might do. I'm speaking more out of hope than expectation."
The SDLP also said there should be no limit to the remit of any appointed specialist and that cost should not be a factor. However, a Northern Ireland Office source suggested that the naming of a forensic scientist was not imminent.
The Irish Times was told that the principle of such an appointment had been agreed by the British and Irish governments, as had a strategy for further investigation of the Disappeared.
"We are talking of an appointment within weeks, possibly months," suggested one source. However it seemed unlikely, the source said, that the remit of any appointed expert would be extended to include other high-profile cases.
The interests of victims and their families are being addressed by a special commission headed by former civil service head Sir Ken Bloomfield, it was suggested.
Last March the Northern Ireland Office awarded extra funding to the PSNI for the creation of a specialist unit to examine so-called cold cases - the 1,800 unsolved murders of the Troubles.
Mr Adams' comments in Dublin followed an admission by the IRA in Derry yesterday that it was responsible for the killing of teenager Kathleen Feeney during rioting in the city in 1973. The IRA had blamed her shooting on the British army and said it shot dead a soldier in retaliation.
That victim's identity was never disclosed. However 11 days later two soldiers were shot dead in an IRA ambush in the Bogside, not far from where Kathleen was killed. The Feeney family yesterday said the statement would bring them closure, a sentiment echoed by Mr Adams.
Earlier this month the body of Armagh man Gareth O'Connor was found in Newry Canal following a tip-off. He had been missing since 2003.
The IRA has already claimed it had identified the graves of nine people it abducted and murdered.
Three victims were found in 1999 while another was uncovered in 2003. In 1999, gardaí recovered the bodies of Eamon Molloy, left in a coffin in a graveyard in Co Louth as well as the remains of John McClory and Brian McKinney, whose remains were found after weeks of digging in a bog in Co Monaghan.
In 2003, the body of Jean McConville was found by accident on a beach in Co Louth.
However, the bodies of at least five others abducted and killed have still to be found. They include Seamus Wright, a member of the IRA from Belfast, who was interrogated and murdered by the IRA in 1972 and Kevin McKee, also from Belfast and another IRA member alleged to have been an army agent.