Berlin (dpa / bb) – A month after the arson attack on a police station in Berlin-Friedrichshain, the Bundesanwaltschaft has offered a10 000 euro reward . It will now be investigated on suspicion of attempted murder, said the Berlin police on Monday. In the attack at least six offenders threw firebombs at the entrance to the police station. Then they lit the shells of fireworks. A 27-year-old building cleaner barely escaped the flames. The perpetrators fled on bicycles. The attack is known to have been caried out by a left extremist group.