In a November 6 press conference, Mexico's National Public Security Minister Oscar Vega Marin said that 333,540 of the some 500,000 local, state and federal police officers have been subjected to background checks, lie detector tests and other vetting procedures. Of these, 15 percent -- some 50,000 agents -- failed, yet only 20 percent of them have been dismissed. 

The official said that measures to clean up the police have been seriously delayed, with only six states (Zacatecas, Coahuila, Nuevo Leon, Guanajuato, Tlaxcala and Colima) carrying the procedures out in full. Vega also identified the four states which have made the least progress in vetting their law enforcement officials: Tamaulipas (which has reviewed 24 percent of its police), Jalisco (23 percent) Chihuahua (21 percent) and Quintana Roo (just 5 percent).

InSight Crime Analysis

These figures fit with previous reports of the slow progress of police reform in Mexico, which is marked by a lack of commitment and political will from local and state authorities. It also telling that three of the states which have made the least progress -- Chihuahua, Tamaulipas and Jalisco -- are among those with the country's highest levels of drug-related violence.

A separate report by security officials, released in August, found that nearly half of the police officers who failed to meet standards were concentrated in just 10 of the country's 32 states. 

While Mexico has been criticized for the slow pace of police reform, it can be argued that this may be better than rushing the process. Sudden police purges can leave states and municipalities shorthanded, and may provide cartels with a supply of recruits with a dangerous amount of in-depth knowledge about the workings of law enforcement agencies.