A prisoner riot at the Brandon Correctional Institute in Manitoba took four hours to bring under control Sunday. Police used stun grenades, water hoses and pepper spray to subdue 27 inmates. Authorities were vague about the possible cause of the riot, the province’s worst since 1996. Gangs are prevalent in Manitoba jails, though. And overcrowding is a potential contributing factor: the jail is designed to hold 157 adult men, 10 young offenders, and four women, according to a government website, but at the time of the riot, it held 282 inmates.