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O’Brien, Denis


Name: O’Brien, Denis

Rank: Detective Sergeant

Reg No: 8288

Station: Dublin Castle

Years of Service: 9

Denis O’Brien, born on 17th June, 1899, at 8 Pim Street, Dublin 8 and was educated at James St. Christian Brothers School. As a youth of 17 years, he fought in the 1916 Rising with the Marrowbone Lane Garrison. After a short term of imprisonment in Richmond Barracks, Dublin he was released as being under age. In 1917 he rejoined ‘C’ Company 4th Battalion, Dublin Brigade and succeeded his brother Patrick as the O/C of that Company. He led his Company through the whole period up to the Treaty. After the Treaty he and his brothers took the Republican side and fought in the Four Courts. Denis was captured and interned in Newbridge, Co. Kildare until 1924. He served as an Accountancy Clerk with the E.S.B. until he joined An Garda Síochána on 9th August, 1933. He was allocated to the Detective Branch and became a member of the section known as the “Broy Harriers”. Promoted to Detective Sergeant on 15th October, 1937. He was survived by his wife, Anne, and two daughters, Fiona and Eitne.


On 9th September, 1942, Detective Sergeant O’Brien was leaving his home at Ballyboden, Co. Dublin when he was ambushed and shot dead by a group of armed men.