Morio Tanimoto

Morio Tanimoto was born in 1960 in the Konohana Ward of Osaka, Japan. He spent most of his life in Osaka Prefecture and was employed for many years as a metal worker before retiring. Available records indicate that he lived a generally stable life for a significant period, maintaining employment and family ties.

In 2008, Tanimoto divorced his wife, an event that reportedly had a lasting emotional impact on him. According to investigative reporting, he later expressed a desire to reconcile with his former spouse, but these attempts were unsuccessful. Following the divorce, his personal circumstances declined, and he became increasingly isolated.

Tanimoto had a documented history of violence prior to the 2021 incident. In 2011, he attacked his adult son, stabbing him in the head in what authorities described as an attempted forced suicide. He was convicted for this offense and served a prison sentence. After his release, he lived alone and experienced ongoing personal and psychological difficulties.

In the years leading up to the Osaka clinic fire, Tanimoto became a patient at the Nishi Umeda Clinic for the Mind and Body, where he received treatment for mental health issues for approximately two to three years. Despite ongoing treatment, he continued to struggle with emotional distress and instability.

A few months before the fire, Tanimoto moved into a residence in Nishiyodogawa Ward, Osaka. Investigators later determined that, in November 2021, he purchased approximately ten liters of gasoline, complying with Japan’s post‑Kyoto Animation arson regulations by presenting identification and stating the fuel was for motorcycle use.

On the morning of 17 December 2021, a fatal fire broke out at a psychiatric clinic on the fourth floor of the Dojima Kita Building in Kita Ward, Osaka.

At approximately 10:20 a.m. local time, Morio Tanimoto entered the clinic carrying a paper bag. The clinic was hosting a scheduled counseling session for patients preparing to re‑enter the workforce, which resulted in an unusually high number of people present at the time.

Survivors later reported that Tanimoto placed the bag near a space heater at the reception area. He then kicked the bag, causing a flammable liquid—later identified as gasoline—to spill and ignite almost immediately. The fire spread rapidly across the clinic floor, filling the enclosed space with thick smoke and heat within seconds.

The clinic had only one effective evacuation route, as emergency stairs and elevators were located outside the treatment area. As a result, many patients and staff were unable to escape. Several victims fled into windowless inner rooms at the back of the clinic, where they were overcome by smoke.

Firefighters received an emergency call at 10:18 a.m. and dispatched approximately seventy fire engines and ambulances. The blaze was largely extinguished by 10:46 a.m., having burned an area of approximately 20 square meters. Despite the limited physical damage, the fire proved highly lethal due to smoke concentration and blocked exits.

Initially, 24 people were pronounced dead at the scene. Over the following days, two additional victims died in hospital from complications related to smoke inhalation, bringing the total death toll to 26. Victims ranged in age from their twenties to their sixties and included both patients and clinic staff. Medical examinations confirmed that most victims died from carbon monoxide poisoning rather than external burns.

Tanimoto himself was found in critical condition inside the building, suffering from severe smoke inhalation and cerebral hypoxia. He never regained consciousness. On 30 December 2021, he died in hospital. His cause of death was officially recorded as carbon monoxide poisoning.