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That deadly Mexican prison riot on Sunday was no random act of violence but rather a calculated escape plan carried out with the help of guards, authorities said, taking a lot of the power out of one of the country's main tools to fight drug violence. In order to loosen the grip of drug cartels, Mexican police rely on being able to arrest, prosecute, and send members to prison. But the escape shows that once cartel members are behind bars, that doesn't neutralize them as a threat.

Nine guards have already confessed to helping the 30 Zetas cartel members escape while their allies killed 44 rival gang members inside the prison, and another nine have been detained for it. The Associated Press reported that the Mexican federal government relies on state prisons like Apodaca, where the escape happened, to take in overflow from the country's six federal prisons. But many of the state prisons are controlled by cartels, so they don't serve as much of a deterrent.

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