The Gardaí were criticised by the commission of investigation into the Dean Lyons case for their handling of the investigation into the Grangegorman killings. In his report, George Birmingham said that the Gardaí had used leading questions in their interviews with Lyons, and had failed to act on a suspicion that Lyons' confession was unreliable. For a period, the gardaí involved in the case failed to act on the knowledge that another man, Mark Nash, had confessed to the crime. They were also criticised for failing to keep adequate records of their interviews with Lyons.