TOKYO — A Japanese court sentenced a man to 23 years in prison on Monday for stabbing a passenger and setting a fire on a Tokyo express train while dressed in a Joker costume on Halloween two years ago, officials said.

The Tachikawa branch of Tokyo District Court found Kyota Hattori, 26, guilty of attempted murder for stabbing and seriously injuring a male passenger in his 70s and of spraying lighter fluid in the train car and then lighting it to try to kill others. Twelve people were injured by the fire, most of them not seriously.

During the trial, Hattori told the court he was so shocked when he learned that his girlfriend had married someone else only six months after they broke up that he decided to carry out the attack so he could end his life by receiving the death penalty, NHK public television reported.

In the ruling, Judge Yu Takeshita said the attack was an “indiscriminate crime with a selfish motive that targeted many passengers who happened to be on the train.”

Prosecutors sought 25 years in prison, arguing that the attack was premeditated and that Hattori had deliberately chosen a special express train that makes fewer stops so passengers would have less chance of escaping. Witnesses said he wore an outfit like the Joker villain in Batman comics.

Defense lawyers asked for 12 years, saying the attack did not constitute attempted murder because most passengers were out of reach when Hattori set the fire.

Gun-related crime is rare in Japan because of strict gun control laws, but there has been a series of high-profile knife attacks in recent years on subways and elsewhere, and there is growing concern about homemade guns and explosives.

Train operators in major cities have stepped up safety measures, including installing security cameras in train cars and conducting more frequent safety drills.

In August 2021, on the day before the closing ceremony of the Tokyo Olympics, a 36-year-old man stabbed 10 passengers on a commuter train in Tokyo in a random attack. The man later told police that he wanted to attack women who looked happy.

The previous month, a 37-year-old man stabbed three passengers with a knife on an airport train in Osaka.