My roommate and I were talking about the disappeared kids, and she really felt strongly that if there was a whiff of bent cops, it was highly likely to be bent cops.
She then told me this story, from about ten years ago.
Every year, the American school where she works takes all the second graders to a camp in the countryside for a few days of being away from parents, nannies, etc, because camp is a good way to make sure you're getting educational experiences outside of the classroom.
Anyway, so they all live in one long building: girls dorm, nurse's station, boys dorm, and spaces for a few teachers and the camp councilors. One dark and stormy night, around 5 am, one of the teachers was awakened to the sound of men shouting. At first she thought it was workers trying to reconnect the power because the lights were gone.
Then she heard the shouts of "chests to the floor!" and in bursts masked men with machine guns. 40 heavily armed masked men had forced their way into the compound and the building. In the other room, the teachers had guns to their heads. In the boys dorm full of second graders, the masked assailants were busy beating the crap out of the camp councilors and staff.
An emergency call was placed to the US embassy pinpointing the distress call, and the embassy immediately got on the phone with the local police department who promised to investigate and then did absolutely nothing. So the embassy responded by sending trucks and helicopters.
The masked assailants turned out to be the police, who claimed they had the wrong address and thought they were busting a meth lab. Mexican law requires all law personnel to wear some kind of identifying insignia. These cops had nothing except body armor, masks, and guns. Coming from a country which bombed the Chinese embassy because of a wrong address, I can understand a little bad intel.
What remains inconceivable is why the assault would continue when you force your way into what is obviously a summer camp for the city elites filled with children.
The shitstorm which followed must have been epic. The son of one of heads of a major Mexican bank was among the terrified students and he came out with four cars of bodyguards to verify with his own eyes that his son was OK. The mayor of the state came to the school personally to apologize. You can bet that whatever shithead was in charge of the operation, and probably a good number of police were probably sent off to hunt chupacabras somewhere godforsaken in the north, if they were allowed to keep their jobs.
I'm constantly reminded that Mexico is largely whodunit territory- who can really draw the line between police incompetence and corruption?