The department responded to a call at 8:38 p.m. and found victims with blood stains when they arrived at the scene. All victims were conscious and one person walked away alone, the department said. No deaths were reported.
According to Japanese public broadcaster NHK, the suspect went to a nearby supermarket, turned himself in, and said to the clerk, “I’m the suspect of the crime that’s now on the news. I’m sick of running away.”
NHK reported that the suspect appears to be in his thirties and the seller said he had blood stains on part of his body.
The incident occurred on a train on the Odakyu Line between Seijogakuen-mae Station and Soshigaya-Okura Station in Setagaya Ward, Reuters reported.
A video captured by one of the passengers and posted on social media shows medical staff putting on plastic gloves on the train.
Violent crimes are rare in Japan, but there have been a number of violent knife attacks by attackers unknown to the victims.
In June 2008, a man drove a pickup truck into a crowd in popular Akihabara, then jumped out of the vehicle and began stabbing pedestrians, killing seven people.
Clarification: This article has been updated to indicate that NHK is Japan’s public broadcaster.