A man who drove into a group of pedestrians in the German city of Heidelberg, fatally injuring one man, is being held on suspicion of murder and attempted murder.
Prosecutors and police are examining whether the suspect, a 35-year-old German student who lives in the city, can be held criminally responsible.
They say there is no evidence of terrorism or extremism and his motive remains a mystery.
Three people were injured in Saturday's crash and one later died.
The suspect got out of his rented car with a kitchen knife and was shot in the stomach by police shortly afterwards.
He has been taken to hospital but authorities say his life is not in danger.
They said he has not responded to initial questioning.