At about 3pm on 12th of March 1955, Constable Mills attended a farmhouse in Pingrup, after he became suspicious of a local farmhand called Eric Thew illegally having a sub-machine gun and using a false name.  

Constable Mills was stationed at Katanning, had previously twice refused to grant a firearms licence to Thew, who had allegedly told his employer that he would "get his own back on Mills one day".

During the search, Constable Mills just found a revolver among Thew's possessions, when he was shot in the side of the face by Thew using the farmers .22 rifle. As Constable Mills tried to reach for the telephone, he was shot a further four times in the head by Thew.

Thew was convicted of murder and sentenced to death on 7th of July 1955 but was later commuted to life imprisonment.