The situation there is so bad, according to a local lawyer, Uriel Márquez Valerio, that inmates managed to invite a musical group into the prison in 2005 to celebrate the birthday of a drug trafficker, who several weeks later found a way to escape.

In recent weeks, the authorities have managed to catch three of the 53 escapees from May and have thrown 51 prison officials, including the director, into jail while the investigation into collusion in the escape continues. The prime piece of evidence against the prison employees was the surveillance system they were supposed to use to monitor inmates. The video, leaked by law enforcement officials and now available on YouTube, recorded the jailbreak in detail.

It was clearly an inside job, one that prompted Interpol to issue an international alert for 11 of the escapees, who were deemed “a risk to the safety and security of citizens around the world.”

One of the escapees, Osvaldo García Delgado, a 27-year-old trafficker with the nickname Vampire, said after he had been re-arrested that the Zetas planned the breakout. Carefully plotted for weeks, the operation was designed to release some top Zeta commanders. Scores of lower-level Zetas were taken along as well.

The Vampire told police interrogators that the prisoners were awakened early one morning and told to dress in their best clothes. He expressed surprise that the guards were doing no guarding that day but instead had become instrumental players in the escape plan.

The men carrying out the escape were dressed in federal police uniforms and drove what appeared to be police vehicles, with lights, sirens and official-looking decals affixed to the sides. There was a helicopter flying overhead as well, giving the operation the air of legitimacy. Since drug cartels frequently recruit law enforcement officials as allies, it is never clear in Mexico whether they will in fact enforce the law  or whether they are impostors.

In this case, the authorities later disclosed that the uniforms worn by the gunmen who carried out the escape were either outright fakes or outdated outfits. The vehicles, which screeched away from the scene with sirens blaring, were not actual police-issue either, the authorities said. All that said, investigators have not ruled out the possibility that corrupt law enforcement officials helped carry out the operation.