MEXICO CITY -- Complicity by guards or other officials is suspected in the escape of 132 inmates from a prison in the northern border state of Coahuila, authorities said Tuesday.
The inmates apparently fled through a 21-foot tunnel carved underneath a carpentry workshop in the prison at Piedras Negras, across the border from Eagle Pass, Texas. They were noticed missing sometime Monday afternoon.
Authorities on Tuesday said they had recaptured three female inmates. Four men also thought to be escapees were killed in a shootout with troops scouring the region in search of the fugitives, they said.
It was the second-largest prison break in the six-year administration of President Felipe Calderon. Mexican prisons, heavily overcrowded in part because of drug-war arrests, are notoriously porous and saddled with corrupt management.
Calderon said Tuesday via Twitter that more than 1,000 inmates had escaped from state prisons in the last six years.
Some of the more infamous past incidents: In the city of Gomez Palacio, which neighbors Coahuila state, a warden was jailed in 2010 for allowing inmates to borrow guns from the guards, leave at night and go on killing sprees; the same year, 140 inmates escaped from a prison in the border state of Tamaulipas, and in 2009 in Zacatecas, guards were caught on security cameras calmly watching as 53 inmates walked out of prison.
This year, a riot that killed 44 inmates in Nuevo Leon state was in fact a cover for the escape of 30 imprisoned members of the Zetas paramilitary force.
Homero Ramos Gloria, state prosecutor for Coahuila, said in a television interview that the complexity of the escape at Piedras Negras -- including the size of the tunnel and the time and effort that went into digging it -- led him to suspect an inside job. The warden and at least two other officials were being interrogated, the prosecutor's office said.
A reward of about $15,000 is being offered for each fugitive.
-- Tracy Wilkinson
Photo: Authorities stand guard outside the Piedras Negras prison near Mexico's northern border on Monday after 132 inmates escaped. Credit: Adriana Alvaro / European Pressphoto Agency