Swiss police have arrested a 15-year-old male suspect in the stabbing of a 50-year-old Orthodox Jew as he walked along a street in Zurich at the weekend. The attack, which left the victim seriously injured, took place in the northern Swiss city on Saturday evening, police said on Sunday. The ongoing investigation by Zurich Canton police and state prosecutors for juvenile offences included the possibility of an anti-Semitic motive, the police statement said. The police were called to the scene because of an argument between several people. The background and the exact course of events were stil…