It was the kind of weekend inmates, guards and their loved ones fear.

A series of coordinated gang fights broke out across six Oklahoma men’s prisons last Sept. 14 and 15. Several corrections guards were injured, 36 inmates were hospitalized and one prisoner died. The violence prompted a statewide prison lockdown that lasted six weeks.

The inspector general’s office concluded that inmates used contraband cell phones — smuggled into facilities by visitors, volunteers or staff — to coordinate the fights. That discovery prompted Gov. Kevin Stitt to issue an executive order directing the correctio...