Munich: A man stabbed four people at a train station near Munich early on Tuesday, killing one and injuring three in an attack a senior politician said did not appear to be politically motivated.
Police earlier said they were checking witness statements that the alleged assailant, a 27-year-old man who was under arrest and the only suspect, shouted slogan.
But Bavarian Interior Minister Joachim Herrmann said he had received no indications that the man had a migrant background, telling reporters: "So far there are no findings that are relevant for state security."
He said the man had shown up in a different part of Germany a few days ago, suspected of using drugs and exhibiting behaviour suggesting he might be mentally disturbed.
Bavarian radio said he used a knife with a 10cm (4 inch) blade in the apparently indiscriminate attack, which took place around 5am (0300 GMT) in Grafing, a commuter town about 32km (20 miles) southeast of the Bavarian capital in southern Germany.
One victim, a 50-year-old, died of stab wounds in hospital shortly after the attack. Police said three other men aged between 43 and 58 were injured, with Bavarian radio saying one was seriously hurt.
Germany, which is playing a supporting role in the fight against IS militant group, has not suffered a major attack by militants on the scale of those that have hit neighbouring France and Belgium.
But with about 260 of the more than 800 home-grown radicals who have joined militant groups in Syria and Iraq having since returned to Germany, ministers have warned an attack is possible and security services are on alert.