A 15-year-old boy has been arrested in connection with a fatal knife attack in the west German city of Solingen (Zou-Li-Gen).
The boy is not the main suspect but is alleged to have known about the attack beforehand.
Two men, aged 56 and 67, and a 56-year-old woman died in the attack on Friday, which German Chancellor Olaf Scholz called a "horrific act".
The Islamic State Group claimed responsibility for the attack.
It did not immediately provide any evidence, and it was not clear how close any relationship with the attacker was.
Police say the 15-year-old connected to the case was detained this morning after two women reported overhearing a conversation between him and a second person in which they discussed the attack.
While he remains in custody, investigators are still trying to establish exactly who carried out the attack.
The suspect's motive is unknown, but Police said they could not rule out that this was a "terrorist-motivated offence".
Police say there was no specific terror threat before the festival, and there was not a large security zone in place.
Chief of Police Markus Röhrl urged people not to speculate on social media and appealed to the public for more information.
Police also revealed that they found "multiple knives" and were looking into whether one of them was involved in the attack.
The attacker reportedly stabbed passers-by "at random" during a festival to celebrate 650 years since the industrial city of Solingen was founded.
Police said the situation on the ground after the attack was "very hectic", which made it difficult to find a perpetrator.
Police confirmed that the attacker "targeted" people's throats and necks.
Source : BBC
