A German serial killer already in prison for the murders of three children went on trial in France on Tuesday over the abduction and killing of a 10-year-old boy during a school trip in 2004.
Martin Ney, dubbed "the man in black", has been charged with murder and kidnapping over the disappearance of Jonathan Coulom at a school holiday camp in western France.
The boy's bed was empty when his roommates woke up in a dormitory at the seaside camp in Saint-Brevin-les-Pins.
More than a month later Jonathan's body was found weighed down by a concrete block in a pond near the town of Guerande, about 30 kilometres from where he had disappeared.
A cord was tied around his neck, feet and hands.
