The Garda Siochána Ombudsman Commission is reviewing the Garda's investigation of a gangland murder case in which a man accused of the killing was acquitted despite the evidence of an informer.
The two-month trial ended on Thursday when Christopher Zambra of Galtymore Road, Drimnagh, Dublin, walked free from court.
He had been cleared by a majority verdict of the shooting dead of John Carroll (33), Charlemont St, Dublin, at Scrumpy Jack's pub in the Coombe area of the south inner city just after 9.30pm on February 18th, 2009.
Detectives investigated the case in the belief that Carroll was murdered as part of a conspiracy between a number of men who wanted him dead, some for personal reasons and some because they owed him large sums of money for smuggling their drugs into the Republic or for buying drugs from him.
The State contended Mr Zambra was a senior figure in that conspiracy.
The murder trial at the Central Criminal Court heard evidence, ultimately rejected by the jury, that Mr Zambra had selected the gunman and an accomplice to drive him to and from the scene by motorbike.
A witness for the State, Joseph O’Brien, gave evidence that he had sourced the motorbike and had been asked to burn it after the killing. He has since entered the witness protection programme.
The commission has received a complaint about the Garda’s conduct during the murder inquiry, with some of the matters being examined centred on the use of Mr O’Brien as an informer.
News that the commission is investigating this element of the case comes just weeks after the conclusion of a 4½ year inquiry into the Garda's alleged misconduct in handling the informer and convicted drug dealer Kieran Boylan from Co Louth.
That inquiry found no evidence to prove Garda wrongdoing. It has led to a major rift between the commission and the Garda Commissioner Martin Callinan over claims and counter claims that the Garda delayed surrendering evidence sought by the commission to such an extent that the inquiry was undermined.
The concerns around the conduct of some gardaí working on the latest case arose two years ago on the occasion of a previous criminal trial linked to the John Carroll murder.
In his charge to the jury two years ago, Mr Justice Barry White noted that after he was arrested on suspicion of murder, Joseph O'Brien had secured two "private audiences" with Det Sgt Adrian Whitelaw and a now-retired detective superintendent, PJ Browne.
He said the two officers had twice disregarded the rules on videotaping of interviews and so he could not know who raised the issues of the witness security programme and immunity, or if any inducements had been given.
“This was wrong, and the superintendent was wrong to engage in this type of conduct,” Mr Justice White said.
He said the jury might consider the Garda to be "well rid of" Mr Browne, "who flouted the law" during the investigation, and that Det Sgt Whitelaw "may not be the type of man you want to see in the force".
He noted that €3,000 found on Mr O’Brien was returned to his partner that night without proper inquiries being made as to whether it was the proceeds of crime.
He said both gardaí had set the recommendations of the Morris tribunal at nought. For years they had broken the Covert Human Intelligence Sources rules in their management of Mr O’Brien as an informer.
It emerged during the trial that Mr O’Brien, his partner and children had entered the witness security programme, probably outside the jurisdiction.
At the conclusion of that trial in July 2011 one man was convicted of murder, two others were cleared and no verdict was reached in relation to Mr Zambra, necessitating the retrial that ended with his acquittal.