By Elisabeth Malkin | NYT | Sept. 18, 2012

MEXICO CITY — The inmates were massed in the prison carpentry workshop when somebody gave the signal. Wedging themselves into a tunnel almost 10 feet below ground, 131 prisoners slid one by one along 23 feet to emerge at the base of the north watchtower.

There they bound and gagged three guards, according to an account provided by prison administrators, cut through a wire fence and walked to freedom.

The prison break on Monday afternoon in the sweltering border city of Piedras Negras, about 150 miles southwest of San Antonio, was the second largest in recent memory. But it was hardly a surprise. Reports of riots, escapes and corruption inside Mexico’s prisons have become an almost routine sideshow in the government’s six-year battle against organized crime.

Officials in Coahuila State said on Tuesday that more than 50 prison guards and administrators were being questioned about the breakout and cast suspicion on their description of events. State prosecutors are seeking warrants to detain the prison director, the shift supervisor and the chief corrections officer.

“We don’t rule anything out,” Jorge Luis Morán Delgado, Coahuila’s secretary for public security, said in an interview. “It takes a long time for 131 inmates to get out through a tunnel.”

He added: “Nobody saw them? That doesn’t sound very convincing to me.”

President Felipe Calderón called the breakout “deplorable” and added in a Twitter message that the “vulnerability of state institutions of justice must be corrected.”

But state prisons have been ignored under Mr. Calderón’s effort to fight drug-trafficking organizations.

The prison population has swelled to overflowing as suspects facing federal drug trafficking and weapons charges have been warehoused in state prisons that are poorly equipped to handle them. Eighty-six of the inmates who escaped on Monday were federal prisoners, officials said.

Piedras Negras is controlled by the Zetas crime network, and the breakout was almost certainly organized by the gang, said Alejandro Hope, a security expert with the Mexican Institute for Competitiveness and a former federal security official.

“State prisons are the forgotten child of justice reforms in this administration,” he said. “There is no champion of prison reform. There are few, if any, organizations dealing with the issue. There is little funding. It is a major sinkhole.”

The state prison in Piedras Negras is not equipped with security cameras. It is also understaffed, Mr. Morán said, because Coahuila has been cleaning up its security forces, including prison staff members, by firing everyone who fails lie detector tests and other exams intended to weed out corruption.

The state has had trouble recruiting new guards and police officers because there is little interest in the jobs, he said.

Mexico’s human rights ombudsman, Raúl Plasencia, accused both the federal and state governments of taking the situation in Mexico’s 431 prisons too lightly. “It is very delicate that somebody who is a very dangerous criminal is sent to a jail where it is easy to escape,” he said.