TOKYO (REUTERS, AFP) - A 24-year-old man, dressed in the costume of the Joker from the Batman series, attacked passengers on a Tokyo train line on Sunday (Oct 31) evening, injuring 17 people as many partygoers headed into the city centre for Halloween gatherings.
The police arrested the suspected attacker, identified as Kyota Hattori, on the spot, the media reported.
A man in his 60s was unconscious and in critical condition after being stabbed. Witnesses said the attacker had spread fluid around the train and started a fire.
One video uploaded on Twitter and broadcast on NHK showed a steady stream of people running away from a train car where, seconds later, a small explosion caused a fire.
Another video showed passengers rushing to squeeze out of the train's windows and onto the platform where the train had made an emergency stop.
"I thought it was a Halloween stunt," one witness told the Yomiuri newspaper, recalling the moment he saw other passengers running in a panic towards his train car. "Then, I saw a man walking this way, slowly waving a long knife."
He said there was blood on the knife.
The attacker carried out the act without showing any emotion, a female passenger said.
"He held a knife and started spreading liquid," she said. "He was committing this act without showing any emotion, just mechanically. I think that brought fear to everyone."
Kyodo reported that the suspect had told investigators he "wanted to kill people and be given the death penalty". He also told them he had spread lighter fluid in the train.
Another video on Twitter showed a bespectacled man dressed in a purple suit and bright green shirt, as worn by the Joker, seated in an empty train puffing on a cigarette, his legs crossed and looking calm.
He can be seen through the window being surrounded by law enforcement in a subsequent clip.
The attack occurred on the Keio express line bound for Shinjuku, the world's busiest rail station, around 8pm.
The line operator said services had been partially suspended after "an incident involving injuries" near Kokuryo in the Japanese capital's western suburbs.
TV footage showed scores of firefighters and police and emergency vehicles outside the station where the train had stopped.
In August, nine people were wounded, one of them seriously, in a stabbing attack on a commuter train in Tokyo, with the suspect later handing himself in after fleeing the scene.
In a separate attack in August, two people suffered burns in an acid attack at a Tokyo subway station.