More than 130 inmates escaped from a prison near the US-Mexico border, highlighting continued chaos in the Mexican penitentiary system.

Authorities discovered a 6.7 meter long tunnel on September 17 leading from Cereso prison’s carpentry room to an exit near a jail tower in the city of Piedras Negras, across the border from Eagle Pass, Texas. The fugitives had used the passage to get outside of the prison walls, then cut through a chain link fence and fled, according to CNN.

Milenio reported that police arrested three female escapees hiding in the carpentry room, though the remaining 129 have yet to be captured. The Mexican government is offering rewards of 200,000 pesos ($15,600) for information leading to the capture of each inmate.

Coahuila state’s attorney general, Homero Ramos Gloria, said 86 of the escaped inmates were serving time or awaiting trials for federal crimes such as drug trafficking. Authorities have detained the prison’s director and two other employees until more information is uncovered about the break.

The prison housed some 730 inmates, but had a capacity for nearly 1,000, the Daily Nation reported Ramos Gloria as saying. 

InSight Crime Analysis

The escapes in Piedras Negras continue a trend of mass prison breaks throughout Mexico in recent years, especially in its northern states. One of the largest came in December 2010 when some 140 inmates escaped from a Nuevo Laredo prison in the northeastern state of Tamaulipas. Escapes have used extreme violence as a distraction. In February this year, the escape of 30 Zetas members from a prison in Apodaca, near Monterrey city, took place after the slaughter of 44 other inmates belonging to the rival Gulf Cartel.

The frequency of Mexican prison breaks poses a major obstacle to effective anti-crime policies, damaging the deterrent effect that incarceration is supposed to pose to criminals. Analysts attribute the chaotic state of Mexican jails to corruption, human rights abuses, and overcrowding. Though the Piedras Negras jail was apparently not overcrowded, the country’s prison system as a whole is running at 123 percent capacity, according to a Global Post series on Latin American prisons.

Mexican authorities have recently sought to tackle the overcrowding problem by contracting private companies to build two private prisons by the end of the year. There is no guarantee that privatization will tackle corruption, though, as the state will still be charged with guarding prisoners.