Garda sources said the exhumation, mass identification, and forensic examination involved would be entering “uncharted waters” given the scale and complexity of the undertaking.
Last Friday, it emerged that the Mother and Baby Home Commission of Investigation found “significant quantities of human remains” involving children up to the age of three, in underground sewage chambers at the former Bon Secours Sisters home.
The recorded deaths of 796 children were previously identified at the Tuam home from 1925 to 1961, many from debility from birth, respiratory diseases, measles, and influenza.
The Irish Examiner revealed that death registers for other mother and baby homes have been in the hands of the State since 2011.
The register of the Bessborough home reveals the names, ages, and causes of death for 470 children and 10 women who died at the institution between 1934 and 1953. More than 270 of these deaths occurred in just six years between 1939 and 1944.
Justice Minister Frances Fitzgerald and Cabinet colleague Simon Coveney said they believed gardaí would become involved in an investigation, while Mary Lou McDonald of Sinn Féin called for a full Garda probe.
Gardaí said it was up to the coroner in north Galway to determine the course of events once he established a belief as to whether the deaths were from natural or unnatural causes.
Experts told the Irish Examiner it would be difficult for the coroner to come to such a view without a forensic examination of the remains — requiring an exhumation.
Forensic experts said there were significant difficulties facing such a process. One forensic expert said there was a massive logistical challenge in excavation and creating a facility to gather and log the remains.
A senior garda said this would be “body identification on an industrial scale”.
Gardaí and Forensic Science Ireland use disaster victim identification to systematically log remains in mass deaths. Forensic experts also flagged serious technical difficulties with identification.
It is not clear if the Nuclear DNA technology available to Forensic Science Ireland is capable of generating DNA profiles from bones more than 50 years old.
Forensic experts pointed out that “reference samples” would be needed from people whose relatives may have been found at the Tuam site in order to cross-check.
In terms of any criminal investigation, Garda sources said that while burying children in a septic tank was morally objectionable, it was not a crime or illegal.
“If the coroner suspects suspicious elements then we have an obligation to investigate,” said a source.
“We don’t have anything to investigate at the moment because there’s no crime and even if there was, there’s no one to prosecute.”
It is thought there are two nuns linked to the Tuam home: one is said to be in her 80s and has dementia, while another is 91 and only visited the home on holidays.
A garda source said reasons for establishing a criminal investigation would be a reasonable suspicion of a crime being committed, such as homicide or neglect, but said it would be almost impossible to prove the latter after so long.
A forensic expert said that 50 years on, the chances of establishing a cause of death were “very low” as except for cases such as strangulation, bones would bear no signs.