A second later, a violent bang slammed against the driver’s side door. Hector jolted, hitting his head on the window. Outside, a man in a dark hoodie was on the ground, clutching his arm. A tire iron lay beside him.

The device was a small, black brick with a lens that looked like a dead, unblinking eye. On its side, a sticker read: . The problem was the manual. It was a tiny, creased booklet, and every word was in Mandarin.

He never did print the confirmation page. And every night since, when Don Julio calls to ask why his son’s voice sounds so thin and tired, Hector just says: “Papá, no compres esa cámara. No leas el manual.”

“Si la luz parpadea en rojo tres veces, luego se apaga, el DVR ha entrado en Modo Testigo. En este modo, grabará lo que sucedió un minuto antes de que usted presionara el botón de encendido. También grabará lo que sucederá un minuto después.”