A 24-hour telephone helpline for police officers introduced two years ago has reduced their suicides to zero in 2018, chief Manolis Koufakis said on Thursday, during a special event at the Hellenic Police headquarters and in the presence of Minister of Citizen Protection Olga Gerovassili, Deputy Minister Katerina-Papakosta Sidiropoulou, the ministry's Secretary General of Public Order Dimitris Anagnostakis and other officials.