Police arrested a 32-year-old woman after six people were hurt in a knife attack on a bus heading to a festival in western Germany.
Authorities said on Saturday that there was no evidence of a political or religious motive.
Three of those attacked are in a life-threatening condition, police said.
The attack took place in Siegen, east of Cologne. The bus was on its way to a festival in the town and at least another 40 people were on board when the attack took place at about 7.40pm on Friday.
Police and prosecutors said the six people wounded were aged between 16 and 30 and all were from the region.
By Saturday three of them had left the hospital after outpatient treatment.
Local authorities planned to go ahead with the festival.
The stabbing in Siegen happened a week after a knife attack in Solingen, a city in the same state of North Rhine-Westphalia, in which a suspected Islamic extremist from Syria who had avoided being deported is accused of killing three people and wounding another eight.
The Solingen attack prompted the governing coalition to draw up plans to tighten knife laws and make deportations easier.
Police said the woman arrested in Siegen was a German citizen with no immigrant roots.
