At least eight people were injured Sunday in a combination stabbing and arson attack on a train in Japan.
The incident occurred in Tokyo, on the Keio express line en route to Shinjuku, at approximately 8:00 p.m. local time.
Witnesses say a man dressed as the Joker, a supervillain from the Batman franchise, spread flammable fluid around the train, then set it on fire.
Passengers told the Yomiuri media outlet that they initially believed the incident was a Halloween prank, as many locals were travelling to Halloween parties at the time.
A small explosion was reported on one train car, with video footage from the scene showing passengers rushing out after the train made an emergency stop.
The suspect also stabbed several passengers. One victim, a man in his 60s, was left unconscious, and is listed in critical condition.
Police have arrested the suspect, a 24-year-old man.