The sole member of the State inquiry into the killing of Gary Douch in Mountjoy Prison has said new hearings are to be held into the 21-year-old Dublin man's violent death.
Grainne McMorrow SC told RTÉ that the inquiry would hold new hearings following the emergence of new evidence.
The evidence came to light after she issued a draft final report to all parties in April last year.
Mr Douch was killed by a mentally ill inmate in an overcrowded cell in Mountjoy Prison in August 2006.
The Commission of Investigation was established in 2007 to probe the circumstances leading to Mr Douch's death.
Under its initial terms of reference, the inquiry was expected to issue a final report by the end of that year.
Ms McMorrow told RTÉ that this initial deadline was "wholly unrealistic".
Speaking to RTÉ's This Week, Mr Douch's mother, Margaret Rafter, said she believed the inquiry should have been concluded at least within two years of her son's death.
She said she did not believe the State had given adequate support to Ms McMorrow's inquiry.
The executive director of the Irish Penal Reform Trust, Liam Herrick, said that the State had failed in its obligations under the European Convention of Human Rights.
He said it failed to deliver a prompt and effective report into Mr Douch's death.
Mr Herrick said the report was of major importance to the issue of how mentally ill prisoners are dealt with within the general prison population.
The Inspector of Prisons, Judge Michael Reilly, has previously said that he was waiting on the McMorrow Inquiry to deliver its final report before he examined the issue of mentally ill prisoners serving period of detention in Irish jails rather than in the Central Mental Hospital.
Grainne McMorrow SC said that she has dealt with the evidence of over 240 witnesses, including individuals and State bodies.
She said her work was delayed by Mr Egan's criminal trial, at which he was convicted of manslaughter by diminished responsibility.
Ms McMorrow was also not paid for almost three years of her work as sole member of the tribunal as her salary agreement expired in January 2010.
However, RTÉ understands that the Department of Justice has entered into discussions with the sole member with a view to agreeing a fee for her work.
The Department of Justice and the Irish Prison Service said they could not comment on the work of the commission which was ongoing.
The commission has to date cost the state €1.9m.
The Dáil has heard that a preliminary report into Mr Douch's death, carried out in 2006 by former civil servant Michael Mellett, identified a number of systems failures within the prisons system that may have contributed to Mr Douch's death.
The findings of the report contained serious implications for the future management of Irish prisons, his report said.
This led to the establishment of a commission of investigation into Mr Douch's killing in 2007, headed by Ms McMorrow.
