David Agren /The Guardian
It was still dark when four men boarded the packed commuter bus heading for Mexico City and ordered the passengers to hand over their valuables.
They gathered up mobile phones and wallets, but as they prepared to leave near the town of Toluca, one passenger stood up, drew a pistol and shot the four assailants, killing their leader instantly.
The three injured robbers stumbled off the bus, but the gunman followed them out and shot them dead at the roadside. Then he returned to the bus, handed back the passengers’ belongings and disappeared into the darkness.
Police in Mexico state, which wraps round the country’s capital like a horseshoe, have deployed hundreds of officers in search of the so-called justiciero – or avenger.
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But many Mexicans – fed up with crime, corruption and impunity – took to social media to praise the unidentified killer. None of the bus passengers have offered information to police, saying it was too dark to see him clearly.