Tokyo (CBS) — A 41-year-old man screaming “You die!” ignited a flammable liquid at the door of a revered animation studio in Kyoto, authorities said, setting off an explosive blaze that rapidly consumed the three-story building. Officials said 33 people were confirmed dead in the fire. Mikihide Daikoku of the  Kyoto fire department said 36 more were injured, 10 of them critically.

Eyewitness cellphone videos show enormous, thick black clouds of smoke billowing from the structure.

The suspect’s identity and motives remained a mystery. Police said the man, who was being treated for injuries he sustained in the fire himself, was neither a current nor former employee of Kyoto Animation Company, a renowned producer of hit TV series. Affectionately known as KyoAni, the company was founded in 1981, and has a devoted fan base worldwide.

Residents of the densely populated Fushimi Ward neighborhood, responding to the terrified screams and pleas for help, assisted in the rescue of victims, many of whom emerged singed, shoe-less and bleeding — some leaving bloody footprints on the sidewalk.

Prime Minister Shinzo Abe expressed his condolences to the victims of the blaze in a tweet, calling it an “arson murder spree.” 

“I’m speechless,” Abe said. “I pray for the souls of those who have passed away. I would like to express my condolences to all of the injured and wish them a speedy recovery.”

Work to recover the dead and wounded from the building was slowed by the instability of the badly damaged structure.

Hayashi says firefighters were still searching inside the building in case anyone else was left behind.

The suspect was burned on his feet, hands and chest, and collapsed nearby while attempting to flee, officials said. As he was treated for the non-life-threatening injuries, police said he confessed would remain in custody. Police said multiple knives were also discovered at the scene.

A witness who saw the suspect being approached by police told Japanese networks that the man admitted spreading gasoline and setting a fire with a lighter. She told NHK public television that the man had burns on his arms and legs and that he was angrily complaining that something of his had been “stolen,” possibly by the company. NHK footage also showed sharp knives police had collected from the scene, though it was not clear if they belonged to the suspect.

Survivors who saw the attacker said he was not their colleague and that he was screaming “(You) die!” when he dumped the liquid and started the fire, according to Japanese media reports. They said some of the survivors got splashed with the liquid.

“He sounded he had a grudge against the society, and he was talking angrily to the policemen, too, though he was struggling with pain,” she told Kyodo News. “He also sounded he had a grudge against Kyoto Animation.” 

A total of 67 employees were on duty, police said. Of those, 10 were discovered in a state of cardiac arrest on the second floor. One victim was quickly declared dead and ten others sustained serious injuries, while 26 others escaped with light injuries.  

Kyoto Animation, better known as KyoAni, was founded in 1981 as an animation and comic book production studio, and its hits include “Lucky Star,” ”K-On!” and “Haruhi Suzumiya.” The company does not have a major presence outside Japan, though it was hired to provide secondary animation work on a 1998 “Pokemon” feature that appeared in U.S. theaters and a “Winnie the Pooh” video.

Footage on Japan’s NHK television showed gray smoke billowing from the charred building. Other footage showed windows blown off.

“There was an explosion, then I heard people shouting, some asking for help,” a female witness told TBS TV. “Black smoke was rising from windows on upper floors, then there was a man struggling to crawl out of the window.”

Witnesses in the neighborhood said they heard bangs coming from the building, others said they saw people coming out blackened, bleeding, walking barefoot, Kyodo News reported.

Rescue officials set up an orange tent outside the studio building to provide first aid and sort out the injured.

Fire department officials said more than 70 people were in the building at the time of the fire and many of them ran outside.

With 33 killed or presumed dead, the fire was the worst mass killing in Japan since a man stabbed and killed 19 people at an assisted living facility in western Tokyo in 2016.

A fire in 2001 in Tokyo’s congested Kabukicho entertainment district killed 44 people in its worst known case of arson in modern times. Police never announced an arrest for setting the blaze, though five people were convicted of negligence. In 2008, 16 people died in a blaze at a movie theater in Osaka, near Kyoto.