Shinji Aoba allegedly started the fire at the first-floor entrance to Kyoto Animation on the morning of 19th July. An eyewitness said the suspect yelled something about the studio stealing the plot of his novel. But police say they cannot confirm whether he ever published one. They say he has never worked for the company.
Kyoto Animation President, Hideaki Hatta, said no one at the studio recognized Aoba and they had never received an email message with his name on it.
Hatta said, "We've never heard of him. I understand he's 41 years old. We would have recognized him immediately if he had contacted us in the past."
Police and fire department officials say they have found what appears to be part of a bucket and a melted piece of plastic they believe is from a lighter.
Investigators suspect Aoba bought gasoline at a nearby gas station and put it in two jerry cans before heading to the studio. Police believe he then transferred some of the gasoline into a bucket so he could splash it inside the building.
Investigative sources say Aoba used to live in Ibaraki Prefecture. He was indicted in 2012 for a convenience store robbery and sentenced to three-and-a-half years in prison.
He moved to Saitama Prefecture after serving his sentence. Sources say he has been living on welfare and was treated for mental health issues.
He was known to be a difficult neighbor. Police were called to the apartment block last year and this year over complaints about noise.
A man in his 40s who lived next door to Aoba says last summer he heard loud music coming from the man's room in the early hours of the morning.
Another neighbor in his 20s says he heard Aoba banging on the wall of his apartment a few days before the attack. The neighbor says he went to see the man to complain, but Aoba grabbed him by the collar, telling him to mind his own business.
The death toll from the blaze has reached 34. Another 34 people were injured. Among them is a South Korean national, according to the country's foreign ministry. She has been hospitalized and is reportedly in a critical condition.
Many people with friends and relatives who worked at the studio say they remain in the dark about their fate.
Shinichi Tsuda, says he has repeatedly called the mobile phone of his daughter, Sachie, but there is no answer. He says she landed a job at Kyoto Animation about 20 years ago after graduating from a vocational school for anime production.
Tsuda says he went to a police station on Friday and was told he would have to wait more than a week for the results of DNA testing of the victims. He says he is trying not to think about anything.
Sixty-nine-year-old Kazuo Okada says his 21-year-old granddaughter worked at the studio. He says he hasn't heard whether she is safe. He says he's waiting to hear something -- anything -- about her.
The woman, Megumu Ohno, started working at Kyoto Animation last year. Okada says her name recently started appearing near the bottom of the ending credits of the studio's films. He says he was excited to see it and felt very proud.
The president of Kyoto Animation says he feels crushed by the loss of colleagues he worked with for many years.
Hideaki Hatta told reporters it's unbearable to think the studio's ideals of producing wonderful anime and sending it out to the world ended up meeting such violence.