Kyoto police are piecing together the evidence behind Thursday’s deadly arson attack that claimed 34 lives and injured dozens of others.

After the attack on Japan’s beloved Kyoto Animation studio, an arrest warrant was issued for the man thought responsible, Shinji Aoba, 41, a resident of Saitama Prefecture, on charges of arson and murder.

The suspect’s motives remain murky. Who is Aoba and why did he commit this horrendous crime? What has emerged is that neither his neighbors nor the authorities were surprised he was involved in an apparently senseless act of violence.

Could, then, the tragedy have been averted? That is something the police, the fire department, the company, the victims’ family members and wider society will be asking in the days and weeks ahead.

A killer strikes

According to NHK, other Japanese media, the police and other sources, two days before the attack, multiple sightings of Aoba were confirmed. On Monday last week he was seen loitering around the parking lot of a convenience store 200 meters from the building.

Seemingly agitated, he was playing with his smartphone. He had two containers with him – possibly, these were later filled with gasoline.

On Wednesday, a teenager spotted a man in a red T-shirt and blue jeans sleeping on a park bench about 500 meters from the studio at 8 or 9pm. He had a cart parked next to him. The description matches the clothing Aoba was wearing when he was arrested after the attack.

On Thursday morning, Aoba bought gasoline from a nearby gas station and was seen carrying the two 20-liter cans towards the studio on a cart. Allegedly, he burst into the studio building screaming “Die!” as he doused the floors with gasoline from a bucket.

He also is suspected of pouring the gasoline in front of all available exits and entrances to the building. He then ignited the gasoline with a lighter – setting fire to himself in the process. Although he escaped from the building on bare, bloody feet, he was apprehended by police.

In the early stages of questioning, while still conscious, Aoba told police that Kyoto Animation had “stolen his novel.” Revenge for alleged plagiarism appears to have been his motive.

However, in media interviews, Kyoto Animation President Hideaki Hatta said he had knowledge of Aoba, did not take outside submissions and did not believe there was any merit to the claim.

Troubled child, troubled man

Over the weekend, a clearer picture began to emerge. According to an article in Weekly Bunshun, he was a middle child, with an older brother and younger sister. His parents were divorced and he lived with his father, in poverty.

In elementary school, he joined the judo club, but had few friends. He was bullied in middle school and started to spend an increasing amount of time alone at home – a so-called hikikomori, or “shut-in.” In Japan, Japan’s hikikomori are increasingly mythologized as people who can turn into violent criminals in a flash. Aoba may fuel this belief.

He attended high school at night, did odd-jobs, worked for the prefectural government, delivered newspapers and worked at convenience stores. His father passed away some time before 2005. In 2006, Aoba was allegedly brought in for questioning by police for stealing underwear. Worse was to follow.

In June 2012, he robbed a convenience store, stealing 20,000 yen (US$185). He was jailed and released in January 2016. He was subsequently placed in a government welfare program for ex-convicts needing special assistance and lived in a partially government-managed facility, but eventually moved into his own apartment.

His neighbors found him alarming. A 27-year-old neighbor, who asked not to be named, said Aoba accused him of making loud noises at night. Aoba grabbed the neighbor by the collar and hair and threatened to kill him.

Local police confirmed that last August there was a complaint against Aoba for playing loud music at night and police had to enter his apartment via the balcony when he refused to open the door.

In the fire he allegedly set, Aoba was severely burned on his face, chest and legs. He is now in a specialist burns unit in Osaka. Police are waiting for him to recover before conducting a more in-depth interrogation.

There are questions about his mental state, but he appears to have been fully capable of planning the attack and waiting for the opportune time.

Mass murderers’ minds

Were there warning signs that should have been heeded? Anonymous death threats were made to the studio, via their website, up to one year before the attack, but police had not identified the person making the threats.

It was not known if they came from Aoba.

In March 2013, a Ministry of Justice-affiliated institute published “Research into Indiscriminate Cases of Mass Murder and Injury.” It limited the case study to 52 incidents in which an individual, without a clear motive, seriously injured or killed people they did not know.

Such incidents, like the attack on Kyoto Animation, are highly disturbing to Japan, a society that generally considers itself safe from violent crime. The study’s goal was to learn from, and perhaps prevent, similar attacks.

The study found five different categories of motive. A grudge against how the individual was treated (42%); anger or envy towards a particular group or entity (19%); a wish to escape society by being imprisoned (17%); a desire to commit suicide or be killed (11.5%); and an interest or desire in murdering other people (9.6%).

Side effects of drug abuse or hallucinations from mental illness were also believed to play parts.

On present evidence, Aoba would appear to fit into the first and possibly fifth categories.

The institute reached some conclusions. Recognizing that many mass murderers had previously been institutionalized, it recommended better risk assessments of violent subjects and comprehensive treatments, to continue after individuals were released back into society.

Aoba was in a prison-release treatment program, but does not seem to have been treated for homicidal tendencies.

Death wish

It’s hard to feel sympathy for the suspect, but with hindsight, patterns that might lead him to commit a violent crime appeared visible in his life story. The study noted the only other solution that might prevent mass murder was to proactively deal with social misfits.

In June 2008, Tomohiro Kato, 25, killed seven people in Akihabara by driving into a crowd. Kato said his crime was an act of revenge, venting his anger and frustration at a society that shunned him.

And in July 2016, Satoshi Uematsu, a former nursing home worker, stabbed to death 19 disabled residents of the home and injured 26 others before turning himself into police. Some have grouped him into the hikikomori. 

“In order to make [these] individuals not feel socially isolated, we need to work with all facilities to address mental illness, and prevent suicidal behavior, so that people feel they have ‘a chance in the world’ and a place they feel at home,” the researchers wrote.

The study concluded that the flip side of untreated suicidal impulses in Japan can also be homicide. This suggests the Kyoto Animation killer could have been suicidal: after all, he almost died in the fire he allegedly lit.

A final irony overhangs his current treatment.

The unwritten rule of capital punishment in Japan is that any intentional act that results in more than three deaths is punished with hanging. While authorities are using every means possible to ensure Aoba recovers and survives so he can be questioned and tried, after medical treatment and judicial proceedings, he is almost certain to receive the death penalty.