Germany’s highest prosecuting authority, the Federal Public Prosecutor’s Office, has taken over the investigation into the knife attack in the western town of Solingen that left three people dead. A spokeswoman for the prosecutor’s office told dpa that it was investigating a main suspect, who handed himself in, on suspicion of membership of the terrorist militia Islamic State. Islamic State previously said that one of its members carried out the stabbing. German police detained what they described as a “real suspect” in connection with the knife attack in Solingen that left three people dead, …