The defendant, Matthew Legault, was charged with aggravated assault on Christopher Chrisjohn at Elgin-Middlesex Detention Centre.
Legault admitted to two physical altercations but claimed consent.
The Crown argued Legault was liable as a principal and as a party to a group assault.
The court found Legault's testimony incredible and unbelievable due to numerous inconsistencies.
While the Crown could not prove beyond a reasonable doubt that Legault as principal caused the "wounding" injuries (nasal bone fractures, gash between eyes) due to a subsequent attack by another inmate, it found him liable as principal for the lesser included offence of assault causing bodily harm.
Ultimately, the court found Legault liable as an aider and abettor for the aggravated assault, concluding that the 34-minute attack was a planned, deliberate, and orchestrated group assault involving Legault and other inmates.