Séamus Dwyer, Pro-Treaty politician, is shot dead at his shop in Rathmines, Dublin, by Anti-Treaty fighters on December 20, 1922.

Dwyer is born in Dublin on November 15, 1886.

Serving as an intelligence officer for the Dublin Brigade of the Irish Republican Army (IRA), and as a Dáil Court judge he is imprisoned by the British in 1921. He is elected unopposed at the 1921 Northern Ireland and Southern Ireland general election for the Dublin County constituency as a Sinn Féin Teachta Dála (TD) in the 2nd Dáil. He votes in favour of the Anglo-Irish Treaty. He stands as a pro-Treaty Sinn Féin candidate at the 1922 Irish general election but is not elected.

Dwyer runs a off-licence/grocery shop in Rathmines and is a member of the Rathmines Urban Council. He marries Marie Molloy in 1914, they have no children. He is a member of the Peace Committee of ten men which sit in May 1922 and bring about the agreement between Michael Collins and Éamon de Valera.

On December 20, 1922, Dwyer is shot dead in his shop at 5 Rathmines Road, Dublin, by anti-Treaty IRA Volunteer Robert Bonfield. At about 4:50 p.m., Dwyer is talking to a customer when a young man enters the shop. Addressing Dwyer, the young man asks “Are you Mr. O’Dwyer?” Dwyer replies yes and the young man says that he has a note for him. The young man reaches into the pocket of his overcoat a draws a revolver. He fires twice at Dwyer at point-blank range and he dies instantly. The customer and a shop assistant give chase but are unable to catch the assassin. Two republicans, Frank Lawlor and the actual assassin, Robert Bonfield, are later killed by Free State forces in revenge for the shooting of Dwyer.

Dwyer is buried in Plot UA 67 South Section, Glasnevin Cemetery, Glasnevin, County Dublin.