In June 1921 the Kinnitty Company of the South Offaly No. 2 Brigade Irish Republican Army (IRA) is ordered to construct a roadblock in the rural area of Coolacrease near Cadamstown as part of county-wide military manoeuvres. The roadblock is located at the boundary of land owned by loyalist farmer William Pearson. At around midnight some of the Pearsons are said to have come to the roadblock and fire a shot or shots as a warning to rebels who are damaging their property. A brief gun battle ensues and a man is injured on each side.
Following official investigation into the identity of the men who attacked the roadblock, Thomas Burke, the IRA Officer Commanding South Offaly No. 2 Brigade, orders that the three brothers Richard, Abraham, and Sidney Pearson are to be executed and their houses destroyed.
On June 30, 1921, about a week after the roadblock shootings, a party of about thirty IRA men arrest Richard and Abraham Pearson. They are taken to their house and held under guard there with their mother, three sisters, younger brother, and two female cousins while the house is prepared to be burned. Their father, William Pearson, and brother Sidney are away from home at the time. The brothers Richard and Abraham Pearson are shot by a firing squad of about ten men, and the house is burned. Richard and Abraham Pearson die after six hours and fourteen hours, respectively.
The medical reports declare that the death of Richard Pearson is due to haemorrhage and shock caused by gunshot wounds to the left shoulder, right groin, right buttock, left lower leg and to the back with the most serious being the wound to the right groin. In the case of Abraham Pearson, death is declared to be the result of shock from gunshot wounds to the left cheek, left shoulder, left thigh, lower third of left leg and through the abdomen.