The Kyoto Animation Co. arson attack suspect has started rehabilitation treatment, including sitting in a wheelchair with the help of care staff, investigative sources said Wednesday.

The July 18 attack on a studio of the anime production company Kyoto Animation, also known as KyoAni, in Kyoto Prefecture, claimed the lives of 36 people and injured many others.

The suspect, Shinji Aoba, 41, has been hospitalized with severe burns he suffered in the incident.

According to the sources, Aoba is also sitting up in his bed with the help of care staff.

The Kyoto Prefectural Police plan to arrest Aoba after his health recovers so they can interrogate him. But his recovery is expected to take a while, the sources said.