[VIDEO] Reporting from Monterrey, Mexico — In the seconds before the gunmen burst into the tiny Lozano Garza jewellery store in this city’s downtown, three shoppers browsed the display cases. Then three men with assault rifles ran in, one after the other, the muzzles of their weapons ablaze. By the time anyone reacted to the gunfire, it was too late. The four people collapsed in the barrage of bullets. One of the gunmen helped another, apparently wounded by a comrade, out of the store. Before the last killer fled, he fired final shots into a customer and the guard. Twenty-three seconds after they came, the gunmen disappeared into the traffic of busy Francisco Madero Avenue, lined with hardware and lighting shops, taco vendors and newsstands. The page of a catalogue on one case fluttered in the breeze. The killers left the jewellery. Nor did they touch the cash register. They paid no heed to the three video cameras that recorded the entire scene.