Formerly a Private in the British Army, serving under Colonel Louis Prescott, Frye was deployed on Africa's Gold Coast, where he and his comrades fought the Ashanti warriors. While fighting overseas, Frye contracted trypanosomiasis, a tropical disease carried by African tsetse flies.
When Prescott's sortie across the Pra River went awry, Frye witnessed the deaths of some of his best friends. Leaving the army shortly afterwards, he continued to feel embittered about the lack of punishment for his former superior. Working as a beer-deliverer with Bennett, Frye took years to exact his revenge.
In 1868, while riding on the back of a cart, Frye used his Whitworth rifle to shoot Prescott through his chest, having left a single white feather as a taunt beforehand. When he returned to the barrel depot where he worked, he was confronted by the Assassins Jacob and Evie Frye who confronted him with the evidence of his murder.
Frye confessed to his crime, revealing that he felt cheated because Prescott got away with the 'murder' of his friends so easily. Immediately after his confession, Frye was taken in by the Metropolitan Police Service.