Their new dominance in the capital is most evident in nightclubs and bars. Some proprietors have been forced to hire security and waitstaff chosen by the narcos themselves. Others take precautions, such as allowing guards to oversee narcotics purchases to keep order. At the club near Cibeles Fountain, a DJ spins old-school cumbia to a young crowd that spends the equivalent of about $10 on mixed drinks. The bathroom where cocaine and Ecstasy are sold for $25 to $50 is dimly lit, but its entrance is wide open.

“Organized crime groups force bars to sell or permit the sale of drugs,” Ernestina Godoy, the city’s chief prosecutor, said in an interview.

The latest daylight shootout took place last week at the Plaza Artz mall, just a few stores down from a Louis Vuitton shop. A woman shot and killed two Israeli men who local media reported distributed drugs to bars in the wealthy Polanco neighborhood. Video footage shows her accomplice firing a high-caliber weapon as he makes his getaway while shoppers duck under tables. One officer was wounded.

A turf war between two gangs, Union Tepito and Anti-Union Force, is often cited as the source of the bloodshed, and authorities say that they’re operating with the help of the most powerful and violent cartels, Sinaloa and Jalisco New Generation. The mall shooting may have even been a showdown between the two cartels, says Mexican risk-consultancy Empra.

Newly freed prisoners provide foot soldiers, some Mexico City authorities say. People have been released from prison in droves thanks to a 2008 criminal-justice overhaul that improved due process but failed to train and vet law enforcement officials before taking full effect in 2016. Many have been let out on technicalities, while some suspects in violent crimes are eligible for bail. The city’s prison population has plunged to about 25,000 this year from more than 41,000 in 2012.

Homicides in the city have climbed so high that killings per 100,000 people are now only 23% below the national average. They were 33% below last year and 41% less in 2017, according to the newly corrected federal data.

Godoy, the prosecutor, says the former administration doctored files so extensively last year that bodies found in Mexico City were registered outside the capital in final reports. The previous government would tally only a maximum of 600 crimes per week, she said. Former Mayor Miguel Angel Mancera, now a senator, hasn’t responded to requests for comment. He’s previously denied the allegations.

A tour bus parks behind a police patrol vehicle in Mexico City, on July 4. Photographer: Alejandro Cegarra/Bloomberg
Reports of altered data are raising questions about whether any government security statistics can be trusted. “States, depending on how they’re conveyed in the news, will often change or doctor their numbers,” said Jack Harary, managing director of Mexico City-based security firm Harary Security Inc.

This week, Sheinbaum pushed through laws requiring harsher sentencing for recidivism and petty crimes like mobile phone theft. She plans to expand the police force this year by 66%.

The government’s actions aren’t sufficient, said Rafael Guarneros, who sits on a neighborhood watch in upscale Condesa. A member of his association, Cristina Vazquez, was murdered in June after reporting crime on her block. Hours after she was found, a man tried to force his way into her apartment for unknown reasons and was arrested. He’d been in and out of prison four times, local media reports.