A man from Syria who has been arrested on suspicion of killingthree people and injuring another eight following a knife attack in western Germany is believed to be a member of Islamic State, a German federal prosecutor has said. Authorities said the 26-year-old man turned himself in and admitted to the crime. A German federal prosecutor spokesperson said the person in custody over the stabbing is suspected of being an ISIS member. On Saturday, Islamic State group claimed responsibility for the attack. The suspect stabbed passers-by who were attending a city festival in Solingen at around 9.45p…