German police ruled out a political or religious motive behind a knife attack in the city of Munich on Saturday and said a detained man suspected of injuring eight people had mental health problems.The arrest of the suspect in his 30s brought calm back to the streets of the Bavarian capital after a tense morning. Police had asked residents to stay home until they find the attacker who had fled on a bicycle.Munich police chief Hubertus Andrae told a news conference that eight people have been lightly injured in the attack and that the suspect was known to police from previous offences, including burglary."We have no indication of a terrorist, political, or religious motive," Andrae said. "I assume it is to do with a psychological disorder of the perpetrator."Police had earlier said they believe the man, who attacked people at several different locations, acted alone.His victims include a 12-year-old boy and a woman.