Minister for Justice Michael McDowell has said he will consider ordering an independent sworn inquiry into the Garda handling of the Grangegorman double murder investigation.
Under little-known provisions relating to Garda disciplinary procedures dating back to a police Act of 1924, Mr McDowell has the statutory power to appoint a person to conduct a sworn inquiry into any allegation of misuse of powers by members of the Garda.
It is believed the inquiry would follow similar lines to that carried out by senior counsel Shane Murphy in relation to Donegal gardaí, which prompted the Morris tribunal. It would also be held in private.
A spokeswoman for the Minister said he would decide whether to order such an inquiry when he receives a Garda report on the case, which saw an innocent man, Dean Lyons, charged with the 1997 murders of two women living in sheltered housing at St Brendan's Psychiatric Hospital in Grangegorman. He was remanded in custody for eight months.
There have been repeated calls for an inquiry from opposition politicians, most notably Labour leader Pat Rabbitte, who has raised the case of Mr Lyons, a former constituent, on a number of occasions in the Dáil.
Welcoming the development, Mr Rabbitte said he was "hopeful it signals a commitment on the part of the Minister to properly investigate [aspects of the case] which are causes of public concern". The main concern was the written confession by Mr Lyons while in Garda custody.
Speaking in the Dáil last Wednesday, Mr Rabbitte said Mr Lyons "made a written statement containing a chronologically correct narrative about the murders in clear grammatical English, and with vivid and chilling accuracy he described the murder scene".
Last month the Garda made an unprecedented public apology to Mr Lyons's family.
Mr Lyons died in September 2000 from a drugs overdose.
In March 1997 Sylvia Sheils and Mary Callinan, who were living in sheltered housing in St Brendan's Hospital, were murdered in their beds in a frenzied attack.
In July Mr Lyons, a homeless heroin addict, was arrested and charged with the murders following the confession.
The following month another man, Mark Nash, who had been arrested in relation to the murder of his girlfriend's sister and her husband in Co Roscommon, also confessed to the murders. Nash, who is serving two life sentences for the Roscommon murders, has never been charged with the Grangegorman killings, and is now unlikely to be.
There have been repeated calls from the sister of Ms Sheils, Stella Nolan, for a public inquiry into the handling of the investigation.
Mr McDowell has said on a number of occasions that he has yet to be convinced that a full public inquiry is warranted.