Attack of the drones: the mystery of disappearing swarms in the US midwest

At twilight on New Year's Eve, 2020, Placido Montoya, 35, a plumber from Fort Morgan, Colorado, was driving to work. Ahead of him he noticed blinking lights in the sky. He'd heard rumours of mysterious drones, whispers in his local community, but now he was seeing them with his own eyes. In the early morning gloom, it was hard to make out how big the lights were and how many were hovering above him. But one thing was clear to Montoya: he needed to give chase.