Found this information on another site, and thought it might be of some assistance.
On the morning of 21 Nov 1920, the IRA men involved stopped outside 119 Baggot Street, Matty MacDonald shared a joke with Jack Keating about the size of the hammer he had brought to force in the door. But the hammer was not needed. MacDonald went on:
We knocked at the front door a maid came along have a letter from the Castle will you deliver this note to Captain Bagelly a one legged man (his record shows the leg amputation and oddly we know that Hardy had a leg amputated as well) . The maid pointing and in we went in. We tapped at the door, opened it and walked in. There were 3 of us. Bagelly was in bed. Lemass, Jimmy and I. I was kind of scared. ‘Captain Bagelly ?’ ‘That’s my name.’ ‘ I suppose you know what we came for. We came for you.’ He was the Judge Advocate General. ‘ I suppose you’ve come for my guns’ he said. One of us, Jimmy Brennan hid it under the bed and he reached behind for it… Slugs and a little more was our reply. ‘Get up.’ He was in pyjamas. Lemass and Jimmy and I fired 2 in the head from the 3 guns. I heard maids screaming afterwards but I was told she was alright. On the ground floor was Jack Foley. A fellow came out with a towel in pyjamas for a bath and Jack stuck him up and he was balls naked. Thinking he was a lodger but he was another British army officer and how we didn’t know about him, we hadn’t any orders about him. MacDonald took a camera and whatever papers he could find. An examination of the body found that Captain G. T. Baggally had been shot on the top of the head, through the left eye and twice in the chest
Hansard reports. When the police arrived every occupant of the house had left, and no witness was available to describe the circumstances. Thomas Whelan was charged with the murder of Capt Baggallay, along with three others - one of whom was called Boyce. A British Army officer, who occupied the room next to Baggally, identified Whelan as the man who covered him with a revolver as another man (who he identified as Boyce) shot Baggally. Both Boyce and Whelan produced evidence that they were elsewhere during the shooting. Boyce's evidence was accepted and he was acquitted along with the other two charged. Even though Whelan had five witnesses (including a priest stationed in Ringsend) who said he was at 9 o'clock mass in Ringsend church at the time of the shootings, he was still found guilty. (Whelan was a member of A Company, 3rd Battalion, Dublin Brigade, IRA.)
5 men were charged with the murder but only Thomas Whelan was found guilty and hanged.