Sky News 
July 26, 2010
Mexican prison guards allowed inmates to walk out of jail with borrowed guns and drive away in official cars so they could carry out drug-related killings, according to authorities.
Following the murders, which included a massacre at a private party last week , the criminals dutifully returned to their cells, Mexico’s attorney general’s office claimed.
Four staff – including a prison director – have been placed under a form of house arrest while investigations continue, but no one has yet been charged.
“According to witnesses, the inmates were allowed to leave with authorisation 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.