(CNN) A German man who allegedly killed one person and injured three others in a knife attack at a train station in Bavaria Tuesday had prompted a police call-out over his erratic behavior two nights earlier, authorities say.

Witnesses told police that the attacker had shouted out "Allahu akbar" and "Infidels must die" as he carried out the attacks, German police officials said at a press conference Tuesday, adding that the suspect had admitted yelling the first statement.

But intelligence services said they knew of no link between him and Islamist networks. Authorities were weighing whether the 27-year-old suspect should be charged or committed for psychiatric treatment.

Terror on first train to Munich

The attack happened shortly before 5 a.m. local time (11 p.m. ET Monday) in Grafing, 23 miles (37 kilometers) east of Munich, officials said.

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