According to a police statement Sunday, an officer fired two warning shots in the air. But the unidentified officer was quoted as saying by Corriere della Sera on Monday that the second shot went off accidentally. Sandri’s death forced the postponement of two Serie A matches and the suspension of another as clashes erupted in cities including Milan and Bergamo. Enraged by the shooting, rioters smashed windows and hurled stones at police cars. In the Italian capital, violent fans rioted into the night, setting trash bins and police vans on fire. About 40 police officers were injured, ANSA reported. A monitoring body set up by the Interior Ministry as a watchdog for soccer violence announced Monday that large groups of violent fans would be blocked from traveling to certain games and, by March 1, all stadiums with a capacity of more than 7,500 will have to provide match stewards. Last season, a policeman was killed in riots following a game between Palermo and Catania in Sicily. The killing prompted authorities to stiffen security measures in and around soccer stadiums, such as barring some fans from traveling to games seen as posing a security threat. “If I were certain that stopping soccer would eliminate the violence problem, I would sign up right away,” Italy coach Roberto Donadoni said. “I don’t think it’s the time to stop, but to act. And most of all, to avoid making judgments the day after.” 160Want local news?Sign up for the Localist and stay informed Something went wrong. Please try again.subscribeCongratulations! You’re all set! AD Quality Auto 360p 720p 1080p Top articles1/5READ MOREStriving toward a more perfect me: Doug McIntyre “We’ll uncover the truth,” said police chief Antonio Manganelli. The policeman who fired the shot was put under investigation by magistrates in Arezzo, a Tuscan town about 125 miles north of Rome where Sandri died. “For now he is under investigation for manslaughter,” Arezzo police chief Vincenzo Giacobbe said, adding that the charges could become more severe. Initial reports said police intervened to stop a scuffle between Sandri’s group of Lazio fans and a group of Juventus fans. Giacobbe indicated Monday that the officer who shot Sandri may have not realized it was a fight between soccer fans. “(The officer) intervened to calm down what appeared to be a fight,” Giacobbe said. “He didn’t know if they were fans. Another thing to clarify is why it was called a fight between fans. We think so, but (the officers on the scene) didn’t know it. They saw with their own eyes that a fight was starting, and banging on a car.” ROME – A police officer was placed under investigation Monday for possible manslaughter in the shooting death of a soccer fan that provoked riots across Italy. Authorities detained four people Monday for taking part in the violence in Rome, where angry fans attacked a police barracks near the stadium and the building housing the Italian Olympic Committee. Gabriele Sandri, a 26-year-old disc jockey from Rome, died after getting hit in the neck by a bullet while sitting in a car. Police said an officer fired shots to disperse a scuffle at a highway rest stop in Tuscany. Police have called the man’s death a “tragic error” and the exact circumstances surrounding it remain unclear.