Japanese police are searching for clues into why a man set a Kyoto anime studio on fire, gutting the building and crushing the hearts of many comic fans around the world.

The man, screaming "You die!" stormed into Kyoto Animation on Thursday, doused it with a flammable liquid and set it on fire, killing 33 people and injuring 36 others. Witness accounts and reports Friday suggested the man had a grudge against the studio.

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Two men pay respects at a makeshift memorial site to honor the victims of Thursday's fire at the Kyoto Animation Studio building, background center, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

Japanese police are searching for clues into why a man set a Kyoto anime studio on fire, gutting the building and crushing the hearts of many comic fans around the world.

Japanese Diet member, Kenta Izumi, left, and Buddhist monk, Matsumoto Genkun, pay respects at a makeshift memorial site in front of burned Kyoto Animation Studio building, background left, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

Media reports said Friday that the suspect told police he set the fire "because (Kyoto Animation) stole novels."

A man prays for the victims of Thursday's fire at the Kyoto Animation Studio building, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans.  (AP PhotoJae C. Hong)

A man prays for the victims of Thursday's fire at the Kyoto Animation Studio building, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A woman prays to honor the victims of Thursday's fire at the Kyoto Animation Studio building, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A woman prays to honor the victims of Thursday's fire at the Kyoto Animation Studio building, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A man gets emotional as he prays for the victims of Thursday's fire at the Kyoto Animation Studio building, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A man gets emotional as he prays for the victims of Thursday's fire at the Kyoto Animation Studio building, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A man places flowers outside the Kyoto Animation Studio building consumed in an arson attack, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A man places flowers outside the Kyoto Animation Studio building consumed in an arson attack, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A man prays for the victims after placing flowers outside the Kyoto Animation Studio building consumed in an arson attack, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A man prays for the victims after placing flowers outside the Kyoto Animation Studio building consumed in an arson attack, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A firefighter is seen through the window of the Kyoto Animation Studio building consumed in an arson attack, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A firefighter is seen through the window of the Kyoto Animation Studio building consumed in an arson attack, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

In this Thursday, July 18, 2019, file photo, firefighters work as smoke billows from a three-story building of Kyoto Animation in a fire in Kyoto, western Japan. Kyoto prefectural police said the fire broke out Thursday morning after a man burst into it and spread unidentified liquid and put fire. (Kyodo News via AP, File)

In this Thursday, July 18, 2019, file photo, firefighters work as smoke billows from a three-story building of Kyoto Animation in a fire in Kyoto, western Japan. Kyoto prefectural police said the fire broke out Thursday morning after a man burst into it and spread unidentified liquid and put fire. (Kyodo News via AP, File)

Police only have said the suspect, a 41-year-old who did not work for the studio, is from near Tokyo and is still hospitalized.

Two men pay respects at a makeshift memorial site to honor the victims of Thursday's fire at the Kyoto Animation Studio building, background center, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

Two men pay respects at a makeshift memorial site to honor the victims of Thursday's fire at the Kyoto Animation Studio building, background center, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

Media reports said Friday that the suspect told police he set the fire "because (Kyoto Animation) stole novels."

The attack shocked Japan and drew an outpouring of grief from anime fans.

Japanese Diet member, Kenta Izumi, left, and Buddhist monk, Matsumoto Genkun, pay respects at a makeshift memorial site in front of burned Kyoto Animation Studio building, background left, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

Japanese Diet member, Kenta Izumi, left, and Buddhist monk, Matsumoto Genkun, pay respects at a makeshift memorial site in front of burned Kyoto Animation Studio building, background left, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A man prays for the victims of Thursday's fire at the Kyoto Animation Studio building, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans.  (AP PhotoJae C. Hong)

A man prays for the victims of Thursday's fire at the Kyoto Animation Studio building, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A woman prays to honor the victims of Thursday's fire at the Kyoto Animation Studio building, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A woman prays to honor the victims of Thursday's fire at the Kyoto Animation Studio building, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A man gets emotional as he prays for the victims of Thursday's fire at the Kyoto Animation Studio building, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A man gets emotional as he prays for the victims of Thursday's fire at the Kyoto Animation Studio building, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A man places flowers outside the Kyoto Animation Studio building consumed in an arson attack, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A man places flowers outside the Kyoto Animation Studio building consumed in an arson attack, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A man prays for the victims after placing flowers outside the Kyoto Animation Studio building consumed in an arson attack, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A man prays for the victims after placing flowers outside the Kyoto Animation Studio building consumed in an arson attack, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A firefighter is seen through the window of the Kyoto Animation Studio building consumed in an arson attack, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

A firefighter is seen through the window of the Kyoto Animation Studio building consumed in an arson attack, Friday, July 19, 2019, in Kyoto, Japan. A man screaming "You die!" burst into the animation studio in Kyoto, doused it with a flammable liquid and set it on fire Thursday, killing dozens of people in the attack that shocked the country and brought an outpouring of grief from anime fans. (AP PhotoJae C. Hong)

In this Thursday, July 18, 2019, file photo, firefighters work as smoke billows from a three-story building of Kyoto Animation in a fire in Kyoto, western Japan. Kyoto prefectural police said the fire broke out Thursday morning after a man burst into it and spread unidentified liquid and put fire. (Kyodo News via AP, File)

In this Thursday, July 18, 2019, file photo, firefighters work as smoke billows from a three-story building of Kyoto Animation in a fire in Kyoto, western Japan. Kyoto prefectural police said the fire broke out Thursday morning after a man burst into it and spread unidentified liquid and put fire. (Kyodo News via AP, File)