Yes, that seems to have been one of the men. The incident in question is pretty widely reported in the media at the time. Here's another witness account of these affairs;
http://www.bureauofmilitaryhistory.ie/reels/bmh/BMH.WS1481.pdf#page=9In a nutshell, what happened was that.
The local IRA went around the Skibbereen area demanding some sort of tax from the local farmers in order to fund their struggle with the Crown Forces. Most farmers paid up but there were many who refused to pay money to who in their eyes; were simply Rebels. More often then not, these were large Protestant landowners or tenant farmers who would have had some Unionist tendencies.
There were two farmers in Lissenihrog, which is a townland adjacent to the farm of my Great-Grandfather. They were prominant Unionists by the names of Sweetman and O'Connoll. The IRA visited them and demanded their 'tax'.
Both of these farmers refused to pay up and news of the IRA imposing taxes on local farmers reached the police who promptly arrested and gaoled the IRA men responsible for collecting this tax. The Irish Times reports that Sweetman and O'Connoll were relucant to testify (for obvious reasons) but were compelled to do so by the authorities.
This effectively was their death sentance as it was common knowledge that these farmers were 'dead men'. Despite all the warnings, Sweetman and O'Connoll stayed on their land until the IRA rounded them up and shot them. As revenge, the Auxillaries billetted in Skibbereen drove up to Mohonagh and burned down a few houses. My great-grandfather's house was one of them.
These affairs are mentioned in Tom Barry's famous book; Guerrila Days in Ireland. Around this time, another volunteer called Patrick Driscoll (a first cousin of my great-grandfather) was shot dead by accident by an overzealous volunteer. Curiously, the week previously a soldier from the Auxillaries died when his rifle discharged whilst they raided Patrick Driscoll's house.
What I am seeking is evidence of records on the British end of things about these events. Surely, various paramilitary organisations, the RIC and British Military Intelligence kept some sorts on these affairs. If Mr. Lunn managed to bring up this question to the General Secretary of Ireland; there must have been some committee or monthly reporting of the goings on in Ireland to Westminster. If that's the case; surely there must be a mechanism to access said records.
Although we all are aware at the slow drip drip of information out of Ireland and Britain over the more recent Troubles. I can imagine that there is still a great deal unknown about the period from the top down to the most local of levels of what went on. This block on certain information can serve to paint our history in a different light.
Here in Ireland you can petition the Department of Agriculture to send you a photocopy of all the historical files relating to a certain folio number provided that you have the permission of the current owner. They sent me back a copy of the contract that my great-grandfather signed in 1917 for the Wyndham Land Act but there were many pages missing in the file. Many of these agreements are still state secrets.
All in all; it's difficult to know where to look for files concerning Ireland pre-Independence. Despite the disasterous records fire in 1922; records might have ended up in Belfast or over in London. I'm very grateful for the assistance and ideas you guys have offered up. It's really interesting to see that my great grandfather was involved (when my grandfather knew nothing of) in the most pivotal period of Irish history.