The death toll from the arson attack on a Kyoto Animation Co. studio last week had risen to 35 as a male victim died at a hospital on Saturday, the police said.
The police have not released the identities of the victims, while some of the injured in the incident are still hospitalized.
Shinji Aoba, who is suspected of entering Kyoto Animation on July 18 and setting fire with gasoline, suffered from severe burns and is still in serious condition.
Although the police have not questioned Aoba yet, investigators searched his home in Saitama near Tokyo on Friday, trying to figure out a motive.
Some evidence has been confiscated, including products of Kyoto Animation, according to investigators.
Some investigators told local media that the studio received repeated email threats, some addressed to specific employees, from the same Internet address between last September and November.