Takayuki Harada, a professor of psychology at Tsukuba University, said that a previous criminal record and joblessness were higher risk factors for future criminal activity than a psychiatric condition.
A neighbor in Mr. Aoba’s building told The Jiji Press that Mr. Aoba had banged on his door this month and rattled the doorknob. When the neighbor answered the door, he told Jiji, Mr. Aoba grabbed him by his chest and hair and shouted: “I will kill you. I have nothing to lose.” According to Bunshun, the neighbor reported the confrontation to the police.
Nobody answered the door on Saturday at any of the units in the two-story apartment complex, which is less than a mile from the nearest train station.
An apartment manager refused to speak to a New York Times reporter, saying that she would not comment unless Mr. Aoba was arrested, referring queries to the local press club. A 37-year-old woman who lives across the street but declined to give her name said she sometimes saw Mr. Aoba passing on the street. She said she had seen the police and ambulances come to the building to check on Mr. Aoba’s apartment after neighbors complained of noise.
Hideaki Hatta, who founded Kyoto Animation with his wife, Yoko Hatta, in 1981, told the Mainichi Shimbun that the company had received a number of death threats in the past two years, although he said Mr. Aoba’s name did not appear in any of the threatening emails.
Mr. Hatta said that he had no idea what Mr. Aoba was talking about when he claimed that Kyoto Animation “stole my novel.” Mr. Hatta said Mr. Aoba had never submitted a manuscript to the company’s novel contest.
Crime is very low in Japan, but there are periodic spasms of random and extreme violence.
“I think the general physical safety that is so noteworthy about Japan heightens the contrast when those things do occur,” said Colin P.A. Jones, a professor at Doshisha Law School in Kyoto.
“Mentally unstable people doing unspeakably violent things happen in the United States and other places,” he said, adding, “I don’t know if you can draw conclusions other than that the contrast is greater” in Japan.