GRAFING, Germany (AP) — A German man yelled out "infidel, you must die" and "Allahu akbar" as he stabbed four people at a Bavarian train station Tuesday, witnesses said. But authorities say they've found no links to any Islamic extremist network and that he appears to be psychologically disturbed.

One victim died in a hospital and three others were being treated for their wounds.

The 27-year-old was taken into custody near the scene at the Grafing Bahnhof just before 5 a.m. and had a 10-centimeter (4-inch) survival knife tucked into his belt, authorities said.

The suspect, whose name wasn't released in line with German privacy laws, had admitted to the crime, said Ken Heidenreich, spokesman for the Munich prosecutor's office in charge of the case.

But Heidenreich said that there were questions about whether the man can be held criminally responsible and that they were evaluating whether he should be taken to a mental institution.

Senior police official Lothar Koehler said the suspect told them he had been taking drugs, and that around the time of the attack he took his shoes off because "he felt bugs on his feet that had caused blisters and were generating intense heat."

Koehler added it wasn't immediately clear whether the suspect was under the influence of drugs at the time of the attack, and they have found no record of any previous narcotics cases against him.

The attack comes at a sensitive time in Germany after the influx of around 1.1 million migrants last year and growing concerns about how the country will deal with them, particularly in Bavaria, their usual state of entry.

Senior police official Guenther Gietl said a woman reported hearing the words "infidel, you must die" as the attack began, and that the suspect himself had admitted yelling "Allahu akbar," Arabic for "God is great."

Koehler said the suspect made a "rather confused impression" during questioning, however, and criminal police official Petra Sandles said there was no evidence that he was a part of any Islamic extremist network.

Authorities said the suspect lived near the central city of Giessen, in the state of Hesse, and it wasn't clear why he had traveled to Grafing, around 30 kilometers (nearly 20 miles) east of Munich.

Police spokesman Irwin Heumann said the 56-year-old victim who died — his age was initially given by authorities as 50 — was attacked aboard the train. He said it wasn't yet clear where the three wounded victims were assaulted.

The other victims were men aged 43, 55 and 58. Their names weren't released.

Heidenreich said one of the survivors had "serious injuries," but that he had no details on whether they were thought to be life-threatening.

At the scene, police forensic experts marked more than 40 bloody footprints — some of them barefoot — on the train platform with chalk numbers and collected evidence, including a cellphone.

Grafing has about 13,500 inhabitants. The rail station where the stabbing happened is some way from the town center. It is served by a Munich commuter line and faster trains on the Munich-Salzburg main line.

Mayor Angelika Obermayr described Grafing as "an absolutely peaceful little Bavarian town."

"Something like this is absolutely new and shakes people deeply — otherwise, they only know this kind of thing from television," she said. "That it could happen here is absolutely stupefying."