The masked 18-year-old man stormed the Scholl secondary school on Monday in the western German town of Emsdetten, wounding as many as 27 people before committing suicide.
The young man, identified only as Bastian B., was known to authorities and due in court on Tuesday for weapons violations, local police said. According to German media reports, he had a fondness for war simulation and computer games.
Wolfgang Bosbach, the deputy head of Chancellor Angela Merkel's Christian Democrats (CDU) in parliament, said it wasthat simulate wanton killing.
"We need effective guidelines to protect children from exposure to different types of media, but we don't need (simulated) killer games that can lead to brutalization," Bosbach was quoted on the Netzeitung news Web site as saying.
Bosbach added that scientificon some children.
Christa Stewens, family minister for the conservative-led state of Bavaria, called for a nationwide, in which players hunt down and pretend to kill each other with guns firing paint balls or laser beams.
"The federal government must finally ban (simulated) killer games... Bavaria has had such a ban in place since 2002," Stewens said in a statement.
She added that children should also be prevented from playing violent computer games.
The federal government has.
The opposition Greens warned against banning violent computer and war games.
Volker Beck, a leading Greens member of parliament, said it would be better to focus the debate on the proper use of computers and not jump to conclusions before it was clear what motivated Bastian B.