A man who survived Thursday’s deadly arson attack on an animation studio in the city of Kyoto has told Jiji Press that the door to the roof of the building was “a difficult type to open” because it was unusual.

The door was “a rare type,” having two metal levers, with one arranged above the other, said the man, an employee of Kyoto Animation Co.

To open the door, the two levers needed to be operated, the man said, recalling that he was “not good at opening the door at first.”

He was working on the second floor of the studio when the three-story building was hit by the arson attack that left more than 30 people dead and scores of others injured.

The door had been closed but not locked when firefighters arrived at the studio for rescue operations. The bodies of 19 people were found on staircases just in front of the door.

Shinji Aoba, 41, who is suspected of setting the studio ablaze, was hospitalized due to severe burns received in the incident. Aoba allegedly splashed gasoline inside the studio after entering the building from its main entrance and set it alight.

Investigative sources also said Sunday that a bag containing four to five knives and a hammer believed to belong to the suspect had been found near the site.

It is believed Aoba planned to use the objects during Thursday’s attack, they said.

On Saturday, Kyoto Prefectural Police obtained an arrest warrant for Aoba on suspicion of arson and murder.

When the arson occurred, about 30 Kyoto Animation employees were on the second floor of the studio, according to the worker.

He said he first noticed the man’s angry voice emanating from the first floor and then heard some women screaming.

About 15 seconds after a female employee on the second floor set off an emergency alarm, black smoke rose up through the spiral staircase to block visibility, the man said.

After managing to move to the balcony, he jumped off to escape the smoke, suffering minor injuries to both elbows.

“I’m angry at the suspect as many colleagues who had worked with me during good times and bad lost their lives in the tragedy,” the man said. “The suspect must be brought to justice after he recovers.”

When he was detained on the street some 100 meters from the studio soon after the incident, Aoba, who was wearing a red shirt at the time of the crime, told police that he had spread the gasoline and lit the fire because Kyoto Animation stole his novel.

According to its website, the famed animation company hosts a novel competition and turns prize-winning works into anime. The company also publishes so-called light novels.

But Kyoto Animation President Hideaki Hatta told reporters on Saturday that he had never heard of the suspect.

The police department suspects that Aoba may have committed the crime out of a one-sided grudge against the company, investigative sources said. The police will work to determine his motive, including an investigation into whether or not he wrote any novels.

Around 5 p.m. Wednesday, a woman in her 80s witnessed a man dressed in red lying on a bench at a park near the studio.

Meanwhile, a woman living near the studio quoted one of her acquaintances as saying that a man in a red T-shirt had been hanging around near the facility in the days before the arson attack.

On the night of July 14, Aoba had trouble with a neighbor while staying at his home in the city of Saitama. Kyoto police suspect he may have come to Kyoto later and stayed around the studio to prepare for the attack.