PIEDRAS NEGRAS, Mexico -- More than 130 inmates escaped from a prison in northern Mexico through a tunnel on Monday, setting off a search by police and soldiers in an area close to the U.S. border.
Authorities in Coahuila state discovered a 7-yard long tunnel, ropes and electric cables they believe were used in the break from the prison in Piedras Negras, a city across the border from Eagle Pass, Texas, according to state Attorney General Homero Ramos Gloria.
Ramos said the prison's director and two other employees were detained for an investigation into the escape of 132 prisoners. The prison houses roughly 730 inmates.
"The fugitives used the tunnel which had an entry and exit hole with a 4-foot diameter," he said. "They cut the chain-link material outside and one by one they got out to a piece of land."
Federal police units and Mexican army convoys were deployed to search for the inmates and authorities in Coahuila state offered rewards of up to $15,000 for information leading to the arrests of each prisoner. Visitors were kicked out of the prison but stayed outside waiting for news of relatives.
Ramos said in a news conference that 86 of the inmates were serving sentences or pending trials for federal crimes, such as drug trafficking, and the rest faced state charges. He said police are investigating a deadly shootout 160 miles south of Piedras Negras after the prison break to determine if any of the four people killed were one of the fugitives.
Other Mexican states have said in the past that they are not prepared to handle highly dangerous federal prisoners.
Coahuila has seen a wave of violence tied to the brutal Zetas cartel's battles with the Sinaloa cartel, allies of the now weakened Gulf Cartel.
Authorities in Coahuila did not say which gang was believed to be behind the prison break.
Last week, Gulf cartel leader Jorge Eduardo Costilla Sanchez was arrested, leading experts to anticipate an increase in violence in parts of northern Mexico as the Zetas Cartel attempted to take over turf.
In December 2010, 153 inmates escaped from a prison in the northern city of Nuevo Laredo, right across Laredo, Texas. Authorities charged 41 guards with aiding the inmates in that escape. Mexico's drug gangs frequently try to break their members out of prison.