Denis O'Brien (police officer)

For other people named Dennis O'Brien, see Dennis O'Brien (disambiguation).

Dennis O'Brien (died 1942), often called "Dinny O’Brien", was a veteran of the Easter Rising, the Irish War of Independence, and the Irish Civil War. He subsequently joined the Garda Siochana and was killed by the IRA.

IRA

O’Brien had fought with his two brothers, Larry and Paddy, in Marrowbone Lane during the Easter Rising of 1916.

Afterwards they had fought together in the Irish War of Independence and subsequently joined the Anti-Treaty IRA during the Irish Civil War. In fact, Paddy was in command of the force which seized The Four Courts in 1922, the act which precipitated the Civil War. Later that year, Paddy was killed in a skirmish with the Irish National Army in Enniscorthy.

O'Brien remained a member of the IRA until 1933 - when De Valera, newly come to power, allied himself with the then legalised IRA against the semi-Fascist Blueshirts. De Valera then issued a call for IRA members to join the police and help confront his political opponents.

Police career

O'Brien was among those who answered the call - an act which at the time seemed quite in accord with his previous career, especially as the Blueshirts were largely composed of the Pro-Treaty veterans from the Civil War era.

O'Brien stayed on in the police when De Valera broke with the IRA in 1934, but also introduced a more Republican constitution in 1937 and abolished the Oath of Allegiance to the British Monarchy.

World War II

During the Second World War O'Brien was a Detective Sergeant in the Special Branch Division of the Garda Siochána, which had its headquarters at Dublin Castle. The Special Branch Division was then largely tasked with hunting down German agents and members of the IRA. Dennis O'Brien regarded this as a necessity due to the fact that the IRA had moved into an active collaboration with the intelligence services of Nazi Germany.

At the time, the IRA regarded the Irish Free State as a de facto extension of the British Empire. Therefore, Irishmen who served the Free State were regarded as traitors. Echoes of these views are still to be found in radical Irish Nationalist publications, such as the one below, even after more than half a century:

"Within a few years, he was fighting and hunting his own, as rapacious as the most dyed in the wool Stater. In his time, he cut down quite a few Republicans, Liam Rice and Charlie McGlade among them, shot while resisting arrest. O’Brien built up his own secret network in pubs, hotels, at stations and among the news vendors on the streets. By 1942, he had turned into a vicious and determined hunter and the IRA gave the order that he was to be executed." (The Concerned Group for Republican Prisoners - see [1]).

Assassination

At 9:45 am on September 9, 1942 at Ballyboden, Rathfarnham, County Dublin, O’Brien left his house and began getting into his car. Three IRA men, wearing trench coats and armed with Thompson sub machine guns, came up the drive and opened fire. The shots from the Thompson smashed the windows of his car, wounding him. He alighted and ran for cover to the gate but before reaching it, he was shot by a single round to the head. Two of the assassins wrapped the Thompsons in their trench coats, mounted their bicycles, and rode towards Dublin. THe commander of the ambush, IRA Chief of Staff Charlie Kerins left on foot, leaving his bicycle behind.

Aftermath

In the aftermath, Gardaí commenced a massive manhunt. Kerins was arrested in a pre-dawn raid and tried by court-martial. As was standard IRA practice, Kerrins refused to respond to the indictment, stating that both the Court and the Irish Free State were illegal bodies. After his fingerprints were identified on the bicycle which was left at the crime scene, he was found guilty, and sentenced to death by hanging. British Chief Executioner Albert Pierrepoint was imported from London to carry out the sentence, in spite of numerous calls for clemency.