Miguel Caballero has a long-established way of welcoming staff into the ranks of his growing security company. He takes out a .38 calibre pistol, loads the chamber with live ammunition, aims it at their stomach and then squeezes the trigger.

The ritual, which also doubles as a test for the luxurious, bullet-proof leather jackets that he makes, always used to take place in Bogotá, Colombia, his native city and a capital with a reputation for violent crime. But today, an increasing number of the shootings happen in Mexico City.