A 24-year-old man has been arrested on suspicion of attempted murder after a knife attack left 17 people injured on Sunday evening.
At least one passenger -- a man in his 70s -- is in critical condition after being stabbed in the chest, police said, according to CNN.
The incident took place on a train in Tokyo where a man, dressed as The Joker, began stabbing people.
Witnesses took video of the moment on the train as the attack unfolded on the Keio line in Tokyo.
In the video, passengers can be seen running through a train carriage to get away from the attacker. Loud bangs and screaming can be heard as flames begin to fill up the carriage with smoke.
The alleged attacker used lighter fluid to set the fire inside the train's carriage, NHK reported citing police.
"I thought it was a Halloween stunt," one witness told the Yomiuri newspaper about the attack. "Then, I saw a man walking this way, slowly waving a long knife."
In the video, passengers are seen jumping out of the train's windows to escape and make their way onto the station platform where the train had made an emergency stop.
According to Japan's public broadcaster NHK, the suspect was arrested after brandishing a knife and starting a fire on a moving train around 8 p.m. (7 a.m. ET) near Kokuryo Station in Chofu City, in Tokyo's western suburbs.
The train was bound for the busy Shinjuku Station in central Tokyo as celebrations took place for Halloween.
The video appears to show the 24-year-old suspect in a 'Joker' costume surrounded by police officers inside a Tokyo train.
This video contains images some viewers may find distressing.
Media reports say the man was arrested by police on the spot.
According to news outlet Kyodo, he told police he adored the character Joker in the Batman comics and looked up to the fictional character.
The Joker is a supervillain in the DC comics and Batman's archenemy.
The 2019 hit movie Joker, starring actor Joaquin Phoenix, featured a scene where he attacks several men on a train after being repeatedly harassed by them.
Shunsuke Kimura, who filmed one of the videos, told the national NHK broadcaster that the scene was "horrifying". "Train doors were closed and we had no idea what was happening, and we jumped from the windows," he said.
Once all passengers left the train, the attacker reportedly sat down and smoked a cigarette as he waited for the police to arrive.
This video contains images some viewers may find distressing.
