Monday’s was the largest jailbreak since 141 inmates broke out of the prison in Nuevo Laredo on Dec. 17, 2010.

Serving as prison warden is one of the most dangerous jobs in Mexico, and numerous wardens have either been assassinated or bent to the will of gangsters.

In the past two years, hit squads have killed prison wardens in Hermosillo (Jan. 3, 2011), Nuevo Laredo (March 15, 2011), Lazaro Cardenas (March 18, 2011) and Saltillo (Dec. 13, 2011), as well as slaying family members of wardens in several other cities.

A month ago, the warden of a prison in Zacatecas, Fabiola Quiroz Zarate, ordered the transfer of dozens of dangerous inmates to other jails. A day later, gunmen broke into her house and kidnapped her and two family members. Neither the 43-year-old Quiroz nor her family members have been seen since.

Unable to bear the threats, or enticed by bribes, or both, some wardens go to the dark side. Perhaps the most extreme case occurred in July 2010, when prosecutors said a prison warden in Durango state allowed inmates to go free at night, handed over weapons and official vehicles and allowed them to carry out three contract killings that left 35 people dead.

Claudia Rodriguez, a columnist for the Quadratin digital news website, wrote Thursday that events this week “reveal to us and confirm that prisons rehabilitate criminals by day while at night they are allowed to leave and, without doubt, are even given guns so they can be paid killers.”

Benitez said the faltering penitentiary system would be one of President-elect Enrique Pena Nieto’s challenges when he takes office Dec. 1.

Since federal prisons cannot hold all those charged with federal crimes related to drug trafficking, thousands of dangerous inmates are handed down for incarceration in less-secure state prisons, he said.

The lax security is evident in periodic news reports about jails with cellblocks equipped with cantinas and apartments with creature comforts.

“Cellphones, prostitutes, drugs, plasma TVs, you name it. If you have enough money, you can live inside the prison as you would outside the prison,” Islas said.