A prison riot at El Castillo penitentiary in Mazatlán, Sinaloa, killed 10 people—including nine inmates and a family visitor—and injured 16 others during visiting hours on October 8, 2026.
The violence broke out Thursday morning inside the prison, which is located in the port city of Mazatlán. State officials said the injured prisoners were taken for medical treatment, while local reports indicated that firearms may have been used during the clash. Security forces from the army, National Guard, navy and state police entered the facility to restore order.
Authorities later said the prison was under control, although security personnel remained on site. Prison visits were suspended as a precaution, and social-work officials began contacting the families of those killed. The Sinaloa attorney general’s office opened an investigation into the cause of the violence and how weapons may have entered the facility.
Officials have not disclosed a motive or identified the groups involved. The incident adds to concerns about prison security in Sinaloa, a state already facing violence linked to rival factions of the Sinaloa cartel.