Denis O’Brien: 1916 veteran shot dead by the IRA in 1942


Pim Street and Upper Basin Street in Dublin 8 are a short five minute walk from each other. They are bound to the north by the sprawling St. James’s Gate Guinness Brewery and to the west by the present day St. James’s Hospital.

In 1916, 8 Pim Street was occupied by the O’Brien family including three brothers – Laurence (MSP34REF1336) aged 25, Patrick (DP2196) aged 18 and Denis (MSP34REF1281) aged 16 – who were members of C Company, 4 Battalion, Dublin Brigade, Irish Volunteers. 16a Upper Basin Street was the home of the Cooney’s including three sisters – Annie (MSP34REF8809) aged 20, Elizabeth (MSP34REF13558) aged 18 and Eileen (MSP34REF8936) aged 17 – who were active with the Inghinidhe branch of Cumann na mBan.

During Easter Week 1916, all six served in Roe’s Distillery, James’s Street and the Jameson Distillery, Marrowbone Lane. They were also all active in the War of Independence and fought in the Civil War on the Republican side.

The Cooney and O’Brien families – already neighbours and friends – were further brought together by the marriage of Denis O’Brien to Annie Cooney in 1926. Elizabeth Cooney married another 1916 veteran Sean Harbourne (MSP34REF1534) on 11 February 1929.

Denis O’Brien, also known as Dinny, joined An Garda Síochána on 9 August 1933 following the election victory of Éamon de Valera’s anti-Treaty Fianna Fáil party. He rose to the rank of Detective Sergeant in Dublin Castle’s ‘Special Branch’.

Denis O’Brien died on 9 September 1942. His file contains the normal solicitor’s correspondence and Department communication which follows the death of a military service pension recipient.  But his file contains no death certificate or offers any other explanation of how he died. There is no hint that Denis O’Brien was gunned down by an IRA unit outside his south County Dublin home at the age of 43.

Letter from James O’Connor (solicitor) dated 28 September 1942 regarding the death of Denis O’Brien. 34D598

The O’Brien brothers

Laurence, known to his friends as Larry, worked in Birmingham, England from 1913 as a civil servant with the Board of Trade. After he was informed that there was a “chance” of “some fighting very soon” in Dublin, he resigned and moved back to his home city with his wife and children.

Typed transcript of Laurence O’Brien’s evidence in front of the Advisory Committee, 24 May 1935. Ref: MSP34REF1336

During Easter Week 1916, Laurence, Patrick and Denis served in Roe’s Distillery, James’s Street for the first two days and then in Jameson Distillery, Marrowbone Lane until the surrender on 30 April. Laurence was arrested and interned in Frongoch, Wales until August 1916. Denis was imprisoned until 6 May 1916 in Dublin but was not deported due to his youth. It is unclear from his file whether Patrick evaded arrest or was also imprisoned.

All three brothers re-joined C Company, 4 Battalion, Dublin Brigade, Irish Volunteers with Laurence being promoted to Company Quartermaster in 1917. Denis took part in an arms-raid on a house in O’Neill’s Court for two revolvers “that had been taken from Marrowbone Lane Distillery by a hostile mob after the surrender”.

Denis served as a First Lieutenant and gave up his employment with the Great Southern Railway Company, Kingsbridge station. He took part in raids on Income Tax Office, Terenure; the manufacture of ammunition at Donnelly’s Bacon Factory; two ambushes of British forces at St. Catherine’s Church, Thomas Street; an operation to execute two Auxiliaries (Auxiliary Police Force) on Crane Street and the prison escape of Frank Teeling (24SP913).

Laurence left C Company about August 1919 to help form a new IRA unit in Bray, County Wicklow which became known as C Company, 6 Battalion, Dublin Brigade. He took part in arms-raids in Bray, Greystones and Shankill and organised an ambush of British forces at Crinken, Bray.

Employed as a storeman for the Dublin Port & Docks Board, Patrick served as Company Captain of C Company, 4 Battalion, Dublin Brigade, IRA until June 1921 when he was replaced by his brother Denis.

During the Truce Period, Laurence was promoted to Vice Battalion Commandant of 2 Battalion, 2 Dublin Brigade. Denis resigned from his job as a Rate and Rent Collector to become a full-time IRA Officer in February 1922 and took part in the arms-raid on the Civic Guards Barracks, the Curragh. Patrick was appointed to the position of the IRA’s Assistant Director of Training around April 1922.

All three brothers took the anti-Treaty side in the Civil War.

Patrick served as O/C (Officer Commanding) of the Four Courts Garrison and received shrapnel wounds in the leg and head during the defence of the building. He escaped from arrest and escaped to Enniscorthy, County Wexford where he led an IRA unit. He received a gunshot wound during an engagement with National Army troops on 4 July 1922 and died of his wounds at the County Home, Enniscorthy, County Wexford on 11 July. Patrick O’Brien’s mother was awarded a £100 wound gratuity in respect of her son’s death in 1922. A reference from Joseph Griffin (MSP34REF40) in 1933 stated that Patrick “lived and died a perfect model of a soldier and man – that is the least I can say of him”.

Hand-written letter dated 5 September 1933 from Marion O’Malley (mother of Ernie) regarding Patrick O’Brien. Ref: 2RB393

Denis entered the Four Courts Garrison in early 1922, took part in its defence and was arrested by National Forces following surrender on 30 June 1922. He was interned in Mountjoy Jail and Newbridge camp, County Kildare until February 1924.

Laurence took part in attacks and engagements against National Army troops in Baltinglass, County Wicklow and Ballymore-Eustace, County Kildare. He was arrested by National forces on 12 July 1922 but managed to escape in August 1922. The subject was appointed Vice Brigade Commandant and then Brigade Commandant in September 1923 of 2 Dublin Brigade. He claims that he remained on the run until around September 1924. He resigned from the IRA in October 1925 and his file includes his resignation letter to Chief of Staff Frank Aiken (MSP34REF59339).

Laurence and Denis were both granted a military service pension at Rank D under the 1934 Act. Laurence was awarded 9 and 22/125 years service and Denis was awarded 9 and 458/500 years service.

The Cooney sisters                                                                                        

Annie, Eileen and Elizabeth (known as Lily) state that they joined the Inghinidhe branch of Cumann na mBan, Dublin in late 1915. Their family home at 16A Basin Street was used as “operating centre” by Con Colbert (DP9900) and Christopher Byrne (MSP34REF101) and “carloads” of arms and ammunition were delivered, stored and then distributed from the house in the weeks leading up to the Rising.

During Easter Week 1916, the three sisters served in the Jameson Distillery, Marrowbone Lane. They were all arrested and imprisoned in Richmond Barracks and Kilmainham Jail until 8 May 1916.

Following their release, the Cooney sisters resumed activity with Cumann na mBan and attended the funerals of Thomas Ashe (1D313) and Richard Coleman (1D15). They attended a training course to learn how to clean, re-assemble and use small arms which Annie claimed proved “valuable” in 1922.

During the War of Independence (January 1919 – July 1921), Annie served as a Company Adjutant and Eileen as Squad Leader in the Inghinidhe branch. All three sisters were engaged in the transportation of material from an IRA munition factory at 119 Parnell Street to their home in Upper Basin Street. The material was then moved to an “official” arms-dump held by their father in his place of work.

Evidence given by Sean Dowling in front of the Advisory Committee, 2 November 1936 in support of Annie O’Brien’s claim. Ref: MSP34REF8809

During this period, Elizabeth worked in a photography shop and claimed that she managed to identify a “British agent” named Maunder who was later deported by the IRA. Maunder, a professional photographer, was alleged to have supplied images to British authorities of IRA leaders Dick McKee (DP23324) and Peadar Clancy (1D412) prior to their arrest.

Hand-written testimony from Elizabeth Curran (née Cooney), signed and dated 3 July 1936. Ref: MSP34REF13558

All three sisters were engaged in carrying arms for IRA units before and after operations on ‘Bloody Sunday’ (21 November 1920). They were also active in the successful prison escape of Frank Teeling (24SP913). Annie was arrested by British forces and imprisoned in Mountjoy Jail from 2 February until 27 May 1921.

Typed transcript evidence by Eileen Harbourne (née Cooney) in front of the Advisory Committee, 24 September 1936. Ref:

All three sisters took the anti-Treaty side in the Civil War (June 1922 – May 1923). They joined the IRA’s occupation of the South Earl Street dispensary and conveyed food, dispatches and arms to and from IRA outposts at the Marrowbone Lane Distillery and the Hammond Hotel, O’Connell Street. The three sisters also collected guns and ammunition and delivered them to Sean Lemass (MSP34REF2078), Ernie O’Malley (34A6) and the wounded Patrick O’Brien who were hiding out in O’Brien’s home at 8 Pim Street. The sisters later joined the IRA’s outpost at the United Service Club, St. Stephen’s Green.

Typed transcript of evidence from Elizabeth Curran (née Cooney) in front of the Advisory Committee, 3 July 1936. Ref: MSP34REF13558

After the Battle of Dublin (28 June – 5 July 1922), the three sisters remained active and smuggled revolvers, ammunition and a National Army officer’s uniform into Mountjoy Jail during July-September 1922 which were used during an unsuccessful escape attempt by IRA prisoners on 10 October 1922. From November 1922 until February 1923, Eileen transported guns for operations undertaken around the city by the Active Service Unit (ASU) of 2 Battalion, Dublin Brigade.

Elizabeth and Aileen claim that they were active with Cumann na mBan until the end of 1923 while Annie states that she remained a member until August 1926.

All three Cooney sisters were granted a military service pension at Rank E under the 1934 Act. Annie was awarded 5 and 4/5 years service; Elizabeth was awarded 6 and 293/500 years service and Eileen was awarded 6 and 52/100 years service.

Hand-written reference from Denis O’Brien dated 9 January 1936 for his brother-in-law Sean Harbourne. Ref: MSP34REF1534

The killing of Denis O’Brien

Former anti-Treaty IRA men, like Denis O’Brien, were initially recruited into the Special Branch in the early 1930s to fight Eoin O’Duffy’s fascist ‘Blueshirts’ which comprised of ex National Army soldiers. Historian Donnacha Ó Beacháin in his 2010 book ‘Destiny of the Soldiers: Fianna Fáil, Irish Republicanism and the IRA, 1926-1973‘ described the new Special Branch (nicknamed the Broy Harries) as providing many anti-Treaty “Civil War veterans with a gun, a salary and an opportunity to patrol their old adversaries” (p. 134).

From the late 1930s onward, the Special Branch’s focus turned to the remnants of the IRA which comprised of many War of Independence and anti-Treaty veterans along with new, young recruits. The IRA’s raid on the Irish Army’s reserve ammunition store in the Phoenix Park’s Magazine Fort (1939); their bombing campaign in England which led to the deaths of several civilians (1939-40) and the development of contacts between the IRA and Nazi German military intelligence prompted the Fianna Fáil government to enact the Emergency Powers Bill to reinstate internment, Military Tribunal, censorship of Republican publications and the death penalty for IRA members during ‘The Emergency’ (Second World War).

Historian Donnacha Ó Beacháin states in ‘Destiny of the Soldiers’ (p. 171) that O’Brien began “hunting down” his former IRA comrades with the “zeal of a convert” within a few years of joining the Special Branch. It was alleged by Conor Foley in ‘ Legion of the Rearguard: Republicanism, Nationalism and the Irish‘ (1992) that O’Brien “was well-known for brutality in the interrogation room and his trigger-happy attitude during raids” (p. 207) in the early 1940s.

The Irish Press (10 September 1942) reported that Denis O’Brien was shot dead by “armed men at the gateway to his home” at ‘Thomond House’, Ballyboden Road, Rathfarnham, South County Dublin. He was setting out for work at about 9.40am on 9 September when he was attacked by three men armed with revolvers and Thompson machine-guns.

At the time of his death, his brother Laurence O’Brien was serving as Private Secretary to Minister Sean Lemass (MSP34REF2078).

Historian Donnacha Ó Beacháin and others have named Archie Doyle (MD45264), a War of Independence veteran, as one of the IRA men who shot O’Brien. Doyle had also been involved in the killing of Minister of Justice Kevin O’Higgins in Dublin in 1927 with Bill Gannon (MSP34REF25776) and Timothy Coghlan. Archie Doyle served in F Company, 4 Battalion during the War of Independence when Denis O’Brien was Company Captain of C Company, 4 Battalion.

The complex political journey of Denis O’Brien encapsulates the tangled relationships and overlapping loyalties that have always defined militant Irish Republicanism.