The Squad, nicknamed the Twelve Apostles, was an Irish Republican Army (IRA) unit founded by Michael Collins to counter British intelligence efforts during the Irish War of Independence, mainly by means of assassination.
On 10 April 1919, the First Dáil announced a policy of ostracism of Royal Irish Constabulary men. At the time Sinn Féin official policy was against acts of violence. Boycotting, persuasion and mild intimidation succeeded against many officers. However others escalated their activities against republicans and in March 1920 Collins asked Dick McKee to select a small group to form an assassination unit.
When this squad was formed, it came directly under the control of the Director of Intelligence or his deputy and under no other authority. The Squad was commanded by Mick McDonnell.
The original 'Twelve Apostles' were Mick McDonnell, Tom Keogh, Jimmy Slattery, Paddy Daly, Joe Leonard, Ben Barrett, Vincent Byrne, Sean Doyle, Paddy Griffin, Eddie Byrne, Mick Reilly and Jimmy Conroy. After some time the Squad was strengthened by the following members: Ben Byrne, Frank Bolster, Mick Keogh, Mick Kennedy, Bill Stapleton and Sam Robinson. Owen Cullen (member of 2nd Battalion) was driver for a short time, and Paddy Kelly of Co Clare for a short time. They were employed full-time and received a weekly wage.
Sometimes the squad was strengthened by members of the Intelligence staff, the Active Service Unit, munition workers and members of the Dublin Brigade, as occasion demanded; Tipperary Flying Column men, Dan Breen, Séumas Robinson, Seán Treacy and Seán Hogan; also Mick Brennan and Michael Prendergast Co Clare. The IRA Intelligence Staff consisted of Director of Intelligence Michael Collins, Deputy Director of Intelligence Liam Tobin, 2nd Deputy Director of Intelligence Tom Cullen, 3rd Director of Intelligence Frank Thornton, Members: Joe Dolan, Frank Saurin, Ned Kelleher, Joe Guilfoyle, Paddy Cadwell, Paddy Kennedy, Charlie Dalton, Dan McDonnell and Charlie Byrne. The Munitions included Mat Furlong, Sean Sullivan, Gay McGrath, Martin Kelly, Tom Younge and Chris Reilly.
On 30 July 1919, the first assassination authorised by Michael Collins was carried out when Detective Sergeant "the Dog" Smith was shot near Drumcondra, Dublin. The Squad would continue targeting plainclothes police, members of the G Division of the Dublin Metropolitan Police, and—occasionally—problematic civil servants. Organisationally it operated as a subsection of Collins' Intelligence Headquarters. Two of the executions by The Squad" were the killing on 21 January 1920 of RIC Inspector William Redmond of the DMP "G" Division and on 2 March 1920 a British double agent John Charles Byrnes.
Further members included Mick Love, Gearoid O'Sullivan, Patrick Caldwell, Charlie Dalton, Mick O'Reilly, Vincent Byrne, Sean Healy, James Ronan, Tom Keogh, Tom Cullen, Paddy Lawson, John Dunne and Johnny Wilson, James Heery. Seán Lemass and Stephen Behan (the father of Irish writers Brendan and Dominic Behan) have also been put forward as members of the Apostles. Understandably, there is no hard evidence to support many of these names; however, those that subsequently served in the Irish Army have their active service recorded in their service records held in the Military Archives Department in Cathal Brugha Barracks, Rathmines. Dr. Andy Cooney is also reported to have been associated with "The Squad". Stephen Behan's involvement in the squad was first made public in 1962 when the BBC broadcast an episode of 'This is your life' This is your life dedicated to Behan; during this broadcast other remaining members of the squad joined Behan on the set of the show.
One of the Apostles' particular targets was the Cairo Gang, a deep-cover British intelligence group, so called since it had either been largely assembled from intelligence officers serving in Cairo or from the Dublin restaurant called The Cairo, which the gang frequented. Sir Henry Wilson brought in the Cairo Gang in the middle of 1920, explicitly to deal with Michael Collins and his organization. Given carte blanche in its operations by Wilson, the Cairo Gang adopted the strategy of assassinating members of Sinn Féin unconnected with the military struggle, assuming that this would cause the IRA to respond and bring its leaders into the open.
The most well-known operation executed by the Apostles occurred on Bloody Sunday, November 21, 1920, when British MI5 officers, linked to the Cairo Gang and significantly involved in spying, were shot at various locations in Dublin (14 were killed, six were wounded). In addition to the "Twelve Apostles", a larger number of IRA personnel were involved in this operation. The only IRA man captured during the operation was Frank Teeling. In response to the killings, the Black and Tans retaliated by shooting up a Gaelic football match between Dublin and Tipperary at Croke Park, the proceeds from which were for the Irish Republican Prisoners Fund, killing fourteen civilians including one of the players, Michael Hogan, and wounding sixty-eight. The Hogan stand at Croke Park is named after him.
The elimination of the Cairo Gang was seen in Dublin as an intelligence victory, but Lloyd George commented dismissively that his men "... got what they deserved, beaten by counter-jumpers...". Winston Churchill added that they were ".. careless fellows ... who ought to have taken precautions".
Some Squad members were hanged in 1921 for the killings on Bloody Sunday, including Thomas Whelan and Patrick Moran. Moran had killed a vet, Patrick MacCormack, who seems to have been an innocent victim.
In May 1921, after the IRA's Dublin Brigade took heavy casualties during the burning of the Custom House, the Squad and the Brigade's "Active Service Unit" were amalgamated into the Dublin Guard, under Paddy Daly. Under the influence of Daly and Michael Collins, most of the Guard took the Free State side and joined the Irish Army in the Irish Civil War of 1922-23. During this conflict some of them were attached to the Criminal Investigation Department and were accused of multiple assassination of Anti-Treaty fighters.
Bill Stapleton went on to become a director in Bord na Mona, Charles Dalton and Frank Saurin became directors in the Irish Sweepstakes. Dalton was the subject of a Kevin Myers article, Myers questioned Dalton living in Morehampton Road in 1940, but did not research his article enough to mention that Dalton was a director in the Sweepstakes at the time. In October 1923, Commandant James Conroy was implicated in the murder of two Jewish men, Bernard Goldberg and Emmanuel 'Ernest' Kah[a]n. He avoided arrest by fleeing to Mexico, returning later to join the Blueshirts.  A later application for an army pension was rejected. The killings were the subject of a 2010 investigative documentary by RTÉ; CSÍ: Murder in Little Jerusalem.