The Dublin-based
Irish Independent wrote that "never even in the worst state of terror in the west and south has the state of affairs which now prevails in the Northern capital been experienced". Michael Collins sent an angry telegram to
Northern Ireland Prime Minister James Craig, demanding a joint inquiry into the killings in accordance with Clause 5 of the recently signed
Craig-Collins Pact. No such joint inquiry took place. As with the McMahon killings one week earlier, it was strongly suspected that an RIC Detective Inspector,
John William Nixon, operating out of the Brown Street Police barracks, had organised the attack. Nixon and several other policemen failed to turn up at roll call at the barracks immediately after the killings. According to Irish historical writer
Tim Pat Coogan, "in the atmosphere of the time neither Craig nor the British could or would prosecute or investigate such men without risk of a serious backlash amongst the Specials Special Constabulary". According to Parkinson, "the raw sectarianism of many violent acts during this period were not confined to large scale incidents such as the Arnon Street or the McMahon murders, nor indeed to any one political or religious group". For instance, the day before the Arnon Street killings, it is believed that Catholics were responsible for throwing a
grenade through the window of the house of Protestant Francis Donnelly, killing his two-year-old son Frank and mortally wounding another son, Joseph (12). ==Notes==