Authorities in Greece are preparing for a wave of protests on the first anniversary of the fatal police shooting of a 15-year old boy.More than 150 people were arrested on Saturday amid fears of a repeat of last year’s demonstrations, which were among the most heated in living memory. Those detained include five Italians and three Albanians. Police say hundreds of people have travelled from countries across Europe to join protests to mark the anniversary of the killing of Alexis Grigoropoulos. A police officer will stand trial in January accused of his murder. Another is charged with attempted murder. The shooting in Athens, exacerbated by anger over economic hardship, provoked violent riots that lasted for two weeks.