Last week, CNN reported that 129 inmates escaped from a Mexican prison near the U.S. border. They did not flee through an underground, 21 foot tunnel, as authorities initially reported. Instead, the inmates simply walked out of the front door.

 Federal and local police launched a manhunt after the inmates escaped Monday, Sept. 17, in Piedras Negras, Coahuila Mexico roughly 150 miles southwest of San Antonio, close to the border town of Eagle Pass, TX.

Officials said that it took prison guards an hour to notice that one-fifth of the prison population was missing.   

“We don’t rule anything out,” Coahuila’s secretary for public security, Jorge Luis Morán Delgado, said, according to the New York Times.

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

Authorities later arrested prison director Miguel Angel Resendiz and 15 other prison employees who were charged with aiding the escape.

The New York Times also noted that President of Mexico Felipe Calderon condemned the escape, calling it “deplorable” and added that the “vulnerability of state institutions of justice must be corrected.”

However, the overflowing state prisons in Mexico are poorly equipped to handle suspects facing federal drug and weapon trafficking and weapons charges. The prosecutor’s office reported that 86 of the escapees were serving federal sentences or awaiting trial for federal offenses.

“You have drug smugglers, rapists, a little of everything,” Thomas Herrera, sheriff of Maverick county in Texas, said, according to the Daily Beast.

Additionally, there is insufficient funding at the state prison in Piedras Negras, which is not equipped with security cameras. According to Delgado, the prison is also understaffed because Coahuila has been cleaning up security forces by firing employees who fail lie detector tests and similar strategies intended to weed out corruption.

 As a result, the state has had trouble recruiting police officers and guards because there is little interest in those jobs, Delgado added.

On the other side of the border, U.S. Customs and Border Protection (CBP) officials said that they were aware of the escape and have been in touch with Mexican officials.

“CBP is aware of the reported jail break in northern Mexico, and out of an abundance of caution, has placed its officers and agents in the Eagle Pass, Texas area on alert,” said spokesman Dennis Smith.” At this point, CBP has no reports of escapees attempting to cross the border.”

U.S. Customs and Border Protection has two stations in Eagle Pass, but Smith declined to say how many agents were stationed there, citing security concerns.

“We will continue coordinating with our Mexican counterparts as we monitor this situation,” Smith said, according to the Los Angeles Times.

 Several mass prison breaks have taken place in Mexico since 2010. Two years ago, over 140 inmates escaped from the Nuevo Laredo prison in the northeastern state of Tamaulipas. Forty one guards were charged with aiding the escape, the largest prison break in recent memory.