McMahon killings

[1] A group of police officers broke into their house at night and shot all eight males inside, in an apparent sectarian attack.

Northern Ireland's police – especially the USC, which was almost wholly Protestant and unionist – were implicated in a number of attacks on Catholic and Irish nationalist civilians as reprisal for IRA actions.

In the first half of 1922, in the words of historian Robert Lynch, the Irish Republican Army (IRA), "would make one final attempt to undermine the ever hardening reality of partition by launching an all out offensive on the recently established province of Northern Ireland".

Lynch writes of the USC: "some were polite and courteous, others merely arrogant and destructive whilst a small anonymous minority set out to kill".

[5] On 23 March 1922, constables Thomas Cunningham and William Cairnside were patrolling Great Victoria Street in the city centre when they were approached by a group of IRA members and shot dead.

[7] McMahon was a prosperous businessman, who owned several pubs in Belfast (one of which was The Capstan Bar on Ann Street) and had at one time been chairman of the Northern Vintners' Association.

In his book, Donegal and The Civil War, Liam Ó Duibhir wrote that "His [McKinney's IRA] ... membership was concealed after the killings as it would have given the police and the loyalist mob an opportunity to justify their actions.

"[9] At about 1:00 am on 24 March 1922, two men wearing police uniforms seized a sledgehammer from a Belfast Corporation workman, who was guarding a building site at Carlisle Circus.

The Nationalist newspaper The Irish News also conducted an enquiry and came to a similar conclusion on the identity of the killers: "it was generally accepted that the members were, of the part-time wholly Protestant, 'B' Class of the Special Constabulary".

This has never been proved, but historian Éamon Phoenix, of Stranmillis College in Belfast, has said there is "strong circumstantial evidence" that District Inspector John Nixon was responsible.

At the funeral Mass for the victims at St Patrick's Church, Rev Father Bernard Laverty told the congregation that even the Black and Tans "had not been guilty of anything approaching this [crime] in its unspeakable barbarity".

Irish Nationalist Party MP Joe Devlin told the British Parliament, "If Catholics have no revolvers to protect themselves they are murdered.

[17] David Lloyd George and Winston Churchill, worried that the violence would collapse the new Northern Ireland administration, organised a meeting in London between Irish republican leader Michael Collins and Sir James Craig, Prime Minister of Northern Ireland, both to try to stop the IRA violence which Collins had been tacitly encouraging and supporting, and to pressure Craig to provide more protection for Catholics.

Craig denied the nationalist assertion that the McMahon killings were part of an anti-Catholic pogrom on behalf of state forces, telling the Parliament of Northern Ireland that, "no such thing has ever been the policy of Protestants here ...

[19][20] No one was ever prosecuted for the killings but District Inspector John Nixon of the Royal Irish Constabulary (RIC) was accused of involvement by historians Tim Pat Coogan and Éamon Phoenix.