Some 10,000 people gathered Saturday in downtown Sarajevo to protest against increasing crime by teenagers in the city over the last few weeks, according to DPA. The protesters gathered outside Sarajevo's cathedral urging municipal authorities and those of Bosnia-Herzegovina to take immediate measures to prevent increasing juvenile delinquency. They then marched through the city and surrounded the presidential buildings and the Sarajevo Cantonal Court, hurling eggs at them. Two days ago, three teenagers attacked 17-year-old student Denis Mrnjavac on a city tram, beating him up and stabbing him for no apparent reason. Mrnjavac died on the way to the hospital. Other passengers on the tram did not try to stop them and some even refused to give a statement, police said. Three weeks ago, three 15-year-old Roma boys attacked a 72-year- old woman outside her home in Novo Sarajevo, pouring petrol over her and setting her alight. Ljubica Djokic-Spasojevic died days later from an infection caused by the severe burns. Late Friday, youngsters started a fight in a disco in downtown Sarajevo, police said. Armin Alikadic, 21, sustained life-threatening injuries when the fight ended with gunshots. At least seven people were injured, three seriously when another fight involving youngsters and their parents broke out Friday night in the central Bosnian town of Kakanj. Media reports said 26 juvenile delinquents, all charged with murder, plus more than 400 other teenagers suspected of serious crimes had walked free in Sarajevo. Under juvenile delinquency laws, and amid a lack of specialized institutions for young offenders, police and courts cannot detain youngsters for more than a few days.