A relative of the knife attacker in southern Germany reportedly called police over his confused state two days before the stabbing. One man was killed and three others wounded in the incident, which occurred on Tuesday.
German police said on Wednesday that the 27-year-old, arrested over the fatal stabbing in Grafing on Tuesday, had told relatives prior to the attack he was taking drugs.
The police spokesman said, however, that the man "had appeared calm." On the advice of police, the suspect was taken by his family to the hospital where he received treatment for mental health problems.
The statement issued on Wednesday came just hours after police also confirmed reports that the man, who lived near the central German city of Giessen in the state of Hesse, had spent a day in a nearby psychiatric clinic after his grandparents showed concern for his well-being.
According to a report in the Bavarian daily "TZ," the man left the hospital on Monday - one day before the fatal stabbing - after his grandparents unsuccessfully tried to have their grandson admitted for psychiatric care.
Grafing 'deeply shaken'
The spokesman for Bavaria's state criminal police, Karl-Heinz Segerer, said that the 27-year-old German suspect stabbed the first victim in a waiting train at the Grafing S-Bahn train station at around 4:50 a.m. local time (0250 UTC) on Tuesday.
The suspect, who was barefoot, then exited the train and stabbed a second person on the train platform and two men who were cycling by. The victims were between the ages of 43 and 58. One of the men remains in critical condition.
Segerer said the knife used was a 10-centimeter (3.9-inch) blade, and added that the suspect was not registered as a resident of Bavaria.
Grafing Mayor Angelika Obermayr said in a TV interview that the stabbing attack in her "absolutely peaceful small town" had left residents "deeply" shaken.
"Something like this is completely new and shocks the people here very deeply," she said.