The reopening of any further investigations into murders in the State in the early 1970s was ruled out yesterday by the Garda Commissioner.
Eight people died as a result of car-bombings and shootings in the State between 1971 and 1973. Nobody was ever charged with any of the murders.
The Commissioner, Mr Noel Conroy, was asked at the Oireachtas sub-committee into the Barron report if he could see a reopening of some of the investigations if he had all the information available.
The Commissioner said having looked at the files and how the investigations were carried out, he could not see how gardaí could advance in any way investigations conducted then.
He said it would be very wrong of him to give false hopes to those people who had lost relatives.
"From a professional viewpoint, I do not see us in a position to develop investigations any further. I'm sorry to say that," the Commissioner said.
Mr Gerard Murphy TD (FG) said in relation to Garda and RUC co-operation the Commissioner seemed to be in contradiction with Mr Dessie O'Malley who at the committee earlier this week indicated there was a total lack of co-operation between the two forces.
The Commissioner said times were very difficult in Northern Ireland then. He had dealt with the RUC over the years.
"Having looked at the files, there were communications between local police officers in both forces and there was very good communication," he said.
All things were gone into with the police in Northern Ireland at the time, he said.
He referred to the murder of Ms Bríd Carr in Lifford, Co Donegal in 1971 and said there was excellent co-operation there.
The Commissioner said he was not sure if gardaí suspected any collusion at the time. They were talking about suspects who came from Northern Ireland, he said.
A number of retired gardaí gave submissions. Mr Hubert Reynolds, a detective superintendent in 1973, said there was very good co-operation between the gardaí and RUC at the time.