Happened yesterday
At least 17 people are injured after a man dressed in a Joker costume, stabbed 17, critically injuring at least one person on a train in Tokyo, yesterday.
It happened on the Keio express line, which was bound for Shinjuku - one of the world's busiest stations - as people were heading out for Halloween parties.
Witnesses say he also spread fluid around the train, and started a fire.
A 24-year-old man is being held on suspicion of attempted murder.
