Kyoto Animation Co. held a memorial service on Sunday for the 36 victims of an arson attack two years ago on one of its studios, one of Japan's worst mass murders.

The company, better known as "KyoAni" at home and abroad, asked fans to refrain from coming to the former site of the studio in Kyoto for fear of the novel coronavirus spreading and posted messages from the company and bereaved families on YouTube instead.

Kyoto Animation Co. holds a memorial service on July 18, 2021, in Kyoto for the 36 victims of an arson attack two years ago on one of its studios. (Photo courtesy of Kyoto Animation Co.)(Kyodo)

The attacker Shinji Aoba, 43, was indicted last December on murder and other charges after remaining hospitalized since soon after the attack on July 18, 2019, for the treatment of life-threatening burns.

Immediately after being detained by police officers near the scene, Aoba said he carried out the attack because the company "stole a novel" from him, according to investigative sources.

Before the attack, Kyoto Animation held public contests in which it invited submissions of draft novels with the promise that the winners could have their works animated. The company denied basing any of its anime on Aoba's submitted works, however.

Photo taken July 20, 2019, shows the fire-ravaged spiral staircase of a Kyoto Animation Co. studio in Kyoto. (Kyodo)

A total of 70 employees were inside the building at the time, and aside from the fatalities, 32 people were left injured.

Aoba was formally arrested in May last year, some 10 months after the attack, after recovering sufficiently from life-threatening burns he sustained in the incident covering 90 percent of his body.

He was indicted in December after experts concluded he was mentally competent at the time and can be held accountable for the crime, but his trial has yet to begin. He is currently detained at the Osaka Detention House.

Photo taken July 18, 2019, from a Kyodo News helicopter shows the three-story studio of Kyoto Animation Co. in Kyoto after a man started a fire there. The studio is known for producing the popular TV animation series "K-On!!" and "The Melancholy of Haruhi Suzumiya." (Kyodo) ==Kyodo

Aoba, from Saitama, north of Tokyo, has admitted to setting fire to the studio with gasoline and investigative sources have quoted him as saying, "I thought I could kill many people by using gasoline."

The number of victims makes the attack one of Japan's biggest-ever mass murders. Aoba's motive as well as his mental competency are expected to be the focus of his trial.

The company, known for a number of popular works such as "K-On!" and "The Melancholy of Haruhi Suzumiya," released in September "Violet Evergarden the Movie," an animation film that victims of the attack had been working on.

It was supposed to be released in January last year but the schedule was pushed back due to the impact of the attack as well as the spread of the novel coronavirus.