Police arrested a 49-year-old man who went on a stabbing rampage during the morning rush hour near a Tokyo subway station after hearing “voices” pushing him to attack people.

Tamotsu Kawamura, a former gang member, allegedly attacked four unsuspecting passers-by with kitchen knives outside the Toyocho subway station in Koto Ward on Tuesday morning. Witnesses said the suspect was restrained by some commuters and station staff until the police arrived.

The four victims, in their 30s to 60s, were rushed to the hospital after the attack and were now reportedly in stable condition, according to the Metropolitan Police Department.

Kawamura, who was also arrested in 2005 for stabbing a man inside a pachinko parlor, said he heard “ultrasonic sound waves” from within his body telling him to stab people at random, reports The Japan Daily Press.