Surprisingly very little is written about this event. Thomas Rush had emigrated to USA in 1913, served un US Army in WW1, and became Naturalised in 1920. He then got a passport to visit his family in Ireland. The British inquest covers what happened. Nothing appears in Witness Statements, and nothing in books covering Roscommon in War of Independence. So I conclude that he was not involved with IRA and seems to have just been hanging out with an IRA group who were drilling
1892 Sep 27 Born Ballaghadereen, Co Roscommon. Ballaghaderreen is a town in County Roscommon, Ireland, but traditionally part of County Mayo,
1913 Arrived USA
1917 Jun 5 Gets US Draft Card
1920 Feb 6, Became naturalised US Citizen
1920 Feb 14 appllies for US passport to leave USA for about 6 months in 1921 to visit his brother in Ireland. He is a Labourer
1921 Jun 12 Shot by Crown Forces in execution of their duty