A senior garda has been appointed to investigate allegations that two gardai in the force's Louth/Meath division stopped a doctor from travelling to Dundalk Garda station to carry out a test on a man held for suspected drink-driving.
The doctor was on his way to the station in Dundalk when two officers from another part of the region stopped his car and told him to return home.
The senior officer is investigating whether the two gardai acted so that the drink-driving suspect would not undergo a blood or urine test within three hours of his arrest, and would therefore have to be freed.
Garda Headquarters would give no details of the investigation yesterday, other than to say: "A senior officer was appointed last week to investigate the incident."
However, it is understood that after an initial appraisal of the events senior officers in Dundalk decided the matter warranted further investigation.
An officer from outside the Louth/Meath division is now to interview all the gardai involved, and the general practitioner, to establish what happened.
The incident, first reported in a weekend newspaper, occurred earlier this month when a businessman from the Border region was taken to Dundalk station, suspected of drink-driving. He agreed to give a blood or urine sample and gardai in Dundalk contacted a doctor in Slane to ask him to conduct the test.
On his way to Dundalk the doctor was stopped at a checkpoint by two gardai from another area, who told him to turn around and go home.
The doctor complied, but was suspicious and contacted another Garda station.
When the sergeant at that station heard what had happened, he arranged to have the doctor driven in a patrol car to Dundalk, where he arrived just in time to carry out the test.
The senior officer now investigating the incident is to examine whether the two gardai at the checkpoint told the doctor that they knew the businessman in Dundalk station, and they did not want the test carried out on him.
According to sources the matter is exceedingly grave as the two gardai who set up the checkpoint could be accused not only of breaches of Garda discipline, but of acting to frustrate a prosecution.