GARDAI are outraged after GSOC started investigating a fourth garda who was a colleague of the sergeant who took his own life last week.
The garda was informed he is now also being investigated by the Garda Siochana Ombudsman Commission in relation to a fatal road traffic accident.
This was the same incident which led the late Sgt Michael Galvin to believe he could be charged with involuntary manslaughter.
Two other gardaí have already been cleared - and while Sgt Galvin had also been cleared he had not been told so before he took his own life a week ago.
Sources said the timing of this investigation was "crass, outrageous and insensitive".
"You couldn't make this up. This whole case must now be taken out of the hands of GSOC," a source said.
"The idea that they should consider a fourth investigation when the station is still in mourning is unbelievable. Everyone is extremely angry."
The Association of Garda Sergeants and Inspectors (AGSI) have said that the GSOC investigation was a factor in the death of Gda Sgt Galvin.
Sources have revealed that GSOC officials carried out a cautioned interview with Sgt Michael Galvin in the company of his solicitor on May 20.
The sergeant told friends that he could not take the stress of the investigation, which had left him feeling like a criminal.
An investigation was launched when an apparent discrepancy arose between Sgt Galvin's account of what happened during the accident in Ballyshannon, Co Donegal last January and CCTV footage.
In a letter to his family, Sgt Galvin said he could not take the pressure any longer.
Earlier this week, a spokesperson for GSOC confirmed to the Herald that they had cleared the officer of any wrongdoing five days before his death.
However, in an interview on RTE yesterday morning Ombudsman Commissioner Kieran Fitzgerald said Sgt Galvin had been cleared on May 27.
"Only on the day before his death, did we finally conclude what our finding would be," he said. Mr Fitzgerald also said GSOC would continue to conduct an investigation into the officer's death, despite calls from his colleagues and widow that they not be involved.
He added that GSOC would commission a peer review of the inquiry.
It is understood it will be carried out by the Police Ombudsman of Northern Ireland.
Garda Commissioner Noirin O'Sullivan will travel to Ballyshannon tomorrow to meet with colleagues of the late Sgt Galvin. She has also asked to meet his family.