Greece: Clashes at High School Rally Police fired tear gas and stun grenades at protesting high school students in Greece's two largest cities Thursday during rallies to mark the fourth anniversary of a deadly police shooting that triggered major riots. The teenage protesters hurled petrol bombs and rocks in Athens, where about 2,000 people marched to parliament chanted: "Cops, Bastards, Child Killers." Protesters throw a petrol bomb against riot police during a student's rally which marks the fourth anniversary of a deadly police shooting that triggered major riots, in the northern Greek port city of Thessaloniki, Thursday, Dec. 6, 2012. Fifteen-year old Alexandros Grigoropoulos was shot dead by police in central Athens on Dec. 6, 2008, sparking riots in Greek cities that lasted nearly three weeks. The police officer convicted of the shooting was jailed for life in 2010. (AP Photo/Nikolas Giakoumidis) Close Three youths were detained for questioning, police said, while a bystander's clothing briefly caught fire but she was uninjured. Police also said a clothing store was looted and a private armored security van was attacked during the brief clashes. There were also clashes in Thessaloniki, Greece's second largest city, where about 1,000 students gathered. Fifteen-year-old Alexandros Grigoropoulos was shot dead by police in central Athens on Dec. 6, 2008, sparking riots in Greek cities that lasted nearly three weeks.