German police on Thursday arrested a mother, 29, on suspicion of throwing her two-month-old baby from a third-storey rental apartment-house balcony in Berlin. The child, who came to rest on a projecting roof, was in hospital with serious injuries. The father, 42, called an ambulance after the incident late Wednesday. A police spokeswoman said the mother, who was treated for shock in a hospital, was suspected of dropping or throwing the infant, a girl, "but we don't yet know exactly why."