On 17 June 1919 about 20 of their friends gathered outside the police station in Ashley Road demanding their release while sending word back to other soldiers at the camp to come down to the town to assist them. About 400 Canadian soldiers gathered; in time, they attacked the police station, intending to release MacDonald and Veinotte. Thereafter, the 400 soldiers ran riot through Epsom, breaking windows and destroying property in a trail of destruction more than a mile and a half long.
When the rioters stormed the police station, it was defended by 16 police officers armed with wooden truncheons. During the ensuing fighting 11 policemen were injured, and Sergeant Thomas Green, aged 51, was fatally wounded when he was hit on the head with an iron bar. He died in Epsom Hospital the next day without having regained consciousness.
Scotland Yard detectives arrested Allan McMaster, 30, a former blacksmith, whom they believed to be the rioters’ leader. However, the Canadian soldiers refused to identify him. Despite this, McMaster and seven other soldiers were put on trial at Guildford in July, accused of rioting and manslaughter. Mr. Justice Darling presided. The accused were: James Connors, 19, private, 13th Canadian Highlanders; Robert Alexander McAllan, 45, C.A.M.C.; Allan McMaster, 30, private, 3rd Canadians; Alphonse Masse, 27, C.A.M.C.; Gervase Porier, 24 C.A.M.C.; Herbert Tait, 29, gunner, 11th Division Canadians; Frank Harold Wilkie, 21, private, 102nd Battalion Canadians, and David Verex, 32, private, Canadian Forestry Corps. The prosecution, which included Cecil Whiteley KC, presented a case which was so ineffectual that the four accused were quickly acquitted of manslaughter, and were found guilty only of rioting. They were sentenced to 12 months imprisonment. Within weeks they were pardoned by the Prince of Wales and returned to Canada.
Back in Canada, McMaster confessed to the murder of Sergeant Green in 1929 and was detained by the Canadian police, but he was released after Scotland Yard said he had been legally dealt with by the Guildford court in relation to Green’s death. This left the case officially unsolved. In 2010, We Are Not Manslaughterers by Martin Knight was published. The book contended the mysterious death of a Canadian soldier in Epsom days after that of Sgt. Green was a revenge killing.