A Polish schoolboy caused chaos after hacking into a city's public transport system and
using a TV-style remote control.
The 14-year-old, described by teachers as a model pupil and an electronics genius, hacked into the transport network in Lodz.
He changes the track points and made at least four trams derail - leaving dozens injured.
The boy told local police he had changed the points on tram tracks across the city for a prank. But in one incident alone 12 people were injured.
Miroslaw Micor, spokesman for Lodz police, said: "He studied the trams and the tracks for a long time and then built a device that looked like a TV remote control and used it to manoeuvre the trams and the tracks."
The boy faces charges of endangering public safety in a special juvenile court.