A high school student was arrested Tuesday for allegedly killing the 71-year-old owner of a photo studio in Koya, Wakayama Prefecture, the previous day, police said.
The youth, identified only as a 16-year-old boarding school student in the prefecture, allegedly beat Koji Kubota to death Monday evening. Neighbors found the victim in his studio at around 7:30 p.m.
The suspect reportedly told police he was in a foul mood and wanted a distraction, and it did not matter who he attacked.
The youth said he used an electric water heater as a weapon against the studio owner.
Police said coroners are trying to determine the exact cause of Kubota's death.
The student showed up at a police station at around 11 p.m. Sunday with an instructor of a cram school he used to attend, according to police.
He told police he punched someone at a photo studio near his high school and injured him.
He told police he had Kubota take a photo of him when he entered the school.
The youth's high school gathered the other 230 students to inform them of the slaying.
At a news conference, the vice principal called the suspect an ordinary student with a calm personality.
"We feel very sorry for what happened. Perhaps our guidance was not enough," one of his teachers said.