An increase in prison violence and escapes is fueled in part by the increasing presence of members of highly organized drug cartels and other gangs in the prisons. In January, a fight between inmates in the Gulf Coast city of Altamira left 31 dead. A total of 171 inmates died in such violence last year, up from 45 in 2007, according to the newspaper Milenio.
Often, the riots and escapes are aided by authorities.
In the most striking case, prison corruption resulted in a massacre outside prison walls in 2010. Guards and officials at a prison in Gomez Palacio in northern Durango state let cartel inmates out, lent them guns and sent them off in official vehicles to carry out drug-related killings, including a massacre of 17 people at a rented dance hall. After carrying out the killings, the inmates returned to their cells, where they were safe from their rivals.
More typical was a prison massacre last July in the border city of Juarez that killed 17 inmates. Surveillance video showed guards standing passively by as two inmates took their keys and opened cell doors to spray bullets into a room where members of a rival gang were reportedly holding an unauthorized party, complete with women and booze.
The Zetas, with their quasi-military discipline, probably have an edge on their rivals from the Gulf cartel, said Benitez, the professor who studies security.
"Once inside, they gain control rapidly," he said.
The Zetas and Gulf cartel split in 2010 and have been fighting bloody turf battles in Monterrey and throughout much of northeastern Mexico since then.
But Benitez said Mexico's prisons are part of two larger problems: rampant corruption and a dysfunctional justice system.
"The prison system is just one part of the larger penal-justice system, and in Mexico the penal reform movement is going very badly," he said.
Authorities agreed there are huge problems.
"The shortcomings that exist in Mexican prisons, insufficient food, inadequate space to sleep, (poor) clothing for inmates, bad medical service, have made the prisons into places where corruption and inequality among inmates proliferates," according to a 2008 report on the nation's prisons, the federal Public Safety Department said
The report recommended legal changes to let more prisoners await trial while on bail, and the construction of more and better jails. Three years and hundreds of inmates deaths later, none of those changes have been carried out.
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