A 15-year-old footballer from Berlin died Wednesday after he was seriously injured in a fight with players from a French team at an international youth tournament, police said.
The teenager "died in hospital as a result of his severe brain injuries" after being hit on the head in the altercation in Frankfurt on Sunday, local police said in a statement.
A 16-year-old player from the French team was arrested following the fight and was still being held in custody, police said.
The brawl occurred following the final whistle in a game between the victim's side JFC Berlin and a team from French second-division club Metz.
Investigators were still looking at the "detailed sequence of events" which led to the young player's injuries, they said.
The victim was seemingly hit "on the head or neck" before he "fell to the floor and had to be resuscitated", police said in a separate statement Tuesday.
The victim, already declared brain dead on Tuesday, was kept on life support so his organs could be donated, a spokeswoman for the Frankfurt prosecutor's office said.
French club Metz said Tuesday it was "profoundly shocked" by the events at the tournament in Frankfurt.
Metz confirmed that a player from its "Performance Programme", a scheme which gives "young footballers... from all over the world access to a high-level training structure", was being held by German authorities.
The suspected attacker "denies having deliberately caused serious bodily harm", the club said.
The tournament organisers also said Tuesday they were shocked by the events, describing them as "unbelievably sad".