During January 2011, Anabel Hernandez's extended family held a party at a favorite cafe in the north of Mexico City. The gathering was to celebrate the birthday of Anabel's niece. As one of the country's leading journalists who rarely allows herself time off, she was especially happy because "the entire family was there. There are so many of us that it's extremely difficult to get everybody together in one place. It hardly ever happens."

Anabel Hernandez had to leave early, as so often, "to finish an article," and it was after she left that gunmen burst in. "Pointing rifles at my family, walking round the room — and taking wallets from people. But this was no robbery; no one tried to use any of the credit cards — it was pure intimidation, aimed at my family, and at me." It was more than a year before the authorities began looking for the assailants. And during that time the threats had continued: one afternoon last June, Hernandez opened her front door to find decapitated animals in a box on the doorstep.

Hernandez's offense was to write a book about the drug cartels that have wrought carnage across Mexico, taking some 80,000 lives, leaving a further 20,000 unaccounted for — and forging a new form of 21st-century warfare. But there have been other books about this bloodletting; what made "Los Senores del Narco" different was its relentless narrative linking the syndicate that has driven much of the violence — the Sinaloa cartel, the biggest criminal organization in the world — to the leadership of the Mexican state.