A gunman who had taken four students hostage at a Moscow public school was detained and all hostages were rescued, the Interior Ministry said Monday. The gunman, a senior student of the Moscow secondary school 263, killed a policeman and a teacher, and injured another police officer, local Vesti-24 TV channel reported. The police evacuated other students and teachers of the school with no one hurt, Itar-Tass news agency quoted the Interior Ministry as saying. The attacker threatened a security guard with a pistol before storming a biology classroom where 10-grade students were having their class, the news TV channel reported. He reportedly took four students hostage while other 16 students managed to escape, according to the ministry. A criminal case was opened over the incident at the school in northeast Moscow, spokesman of the Russian Investigative Committee Vladimir Markin said.