The events of that morning rocked Britain’s spy network in the Capital to the core and in effect destroyed it as a viable espionage force. Michael Collins justified what by necessity assassins’ work with the words:
My one intention was the destruction of the undesirables who continued to make miserable the lives of ordinary decent citizens. I have proof enough to assure myself of the atrocities which this gang of spies and informers have committed. If I had a second motive it was no more than a feeling such as I would have for a dangerous reptile. By their destruction the very air is made sweeter… For myself, my conscience is clear. There is no crime in detecting in wartime the spy and the informer. They have destroyed without trial. I have paid them back in their own coin.
That afternoon the Crown Forces raided Croke Park where Dublin were playing Tipperary and proceeded to open fire on the teams and spectators, killing 14 innocent people (including two young boys and a 26-year-old woman). One of the dead was Michael Hogan who was playing for Tipperary that day.
Controversy as to who fired first was immediate with the Crown Forces insisting they were shot at before returning fire. However the most likley explanation is that members of the Auxilirary Division of the RIC fired warning shots in the air to panic the crowd and other members out of sight took it upon themselves to open up under the impression that IRA men in the crowd had targeted them.
A DMP Constable recounted to the Official Inquiry held in December 1920 by the British Military that:
‘On Sunday 21st inst. I was on duty outside the main entrance to Croke Park in Jones’s Road. At about 3.25 p.m. I saw six or seven large lorries accompanied by two armoured cars, one in front and one behind, pass along the Clonliffe Road from Drumcondra towards Ballybough. Immediately after a small armoured car came across Jones’s Road from Fitzroy Avenue and pulled up at the entrance of the main gate. Immediately after that, three small Crossley lorries pulled up in Jones’s Road. There were about ten or twelve men dressed in RIC uniforms in each. When they got out of the cars they started firing in the air which I thought was blank ammunition, and almost immediately firing started all round the ground.’
That night two senior members of the Dublin IRA, Dick McKee and Peadar Clancy and a hapless civilian, Conor Clune, all of whom had been captured the previous day were done to death inside Dublin Castle ostensibly while ‘attempting to escape’.