It's shocking even in a country known for brutal violence and rampant corruption -- prison officials in Mexico are accused of allowing inmates to
leave the guarded facility to commit a series of drug-related revenge murders. The attacks included a massacre last week that left 17 people dead.
According to the nation's Attorney General's Office, inmates were given weapons and official vehicles to commit their crimes, then simply returned to their cells afterwards.
"According to witnesses, the inmates were allowed to leave with authorization of the prison director... to carry out instructions for revenge attacks using official vehicles and using guards' weapons for executions," office spokesman Ricardo Najera said at a news conference.
The director of the prison in northern Mexico and three other officials were placed under a form of house arrest pending further investigation.
The inmates are suspected in three mass shootings, including the July 18 attack on a party in a town near the prison, which left 17 people dead after gunmen fired indiscriminately into the crowd.
Police found more than 120 bullet casings at the scene, and Najera said tests matched those casings to four assault rifles assigned to guards at the prison. Similar ballistics tests linked the guns to shootings at two bars that killed 16 people in February and May.
Interior Secretary Francisco Blake said the stunning accusations "can only be seen as a wake-up call for authorities to address, once again, the state of deterioration in many local law enforcement institutions... we cannot allow this kind of thing to happen again."