The senior counsel appointed by government to investigate the killing of Gary Douche at Mountjoy Prison has undertaken to complete the investigation free of charge.

Gráinne McMorrow was appointed in 2007 to head up the commission of investigation into the circumstances that led to the killing of the 20-year-old by fellow inmate Stephen Egan. Egan, of Belcamp Crescent in Coolock, Dublin, was found not guilty of the murder of his cellmate but guilty of manslaughter by reason of diminished responsibility.

Egan had been in the Central Mental Hospital but was later transferred to Mountjoy, where he was put in a cell with others without the medication he needed for his mental illness. He beat Douche to death and smeared excrement on his face after subjecting him to a terrifying ordeal on 1 August, 2006.

A total of 112 possible witnesses were identified and scheduled to give oral evidence at the private hearings, including the five inmates who shared a basement holding cell with the victim and his killer. The prisoners did not appear as witnesses during Egan's trial.

McMorrow had hoped that her extensive report into the prison death and management of mentally ill inmates would be ready to be presented to justice minister Dermot Ahern by January last, but it was delayed when some of the witnesses' testimonies had to be re-scheduled.

"Given the crisis state of the country's economy and recession, I undertook to finish the work on my own time without further pay," McMorrow told the Sunday Tribune.