A man held over the murder of his probation officer in the city of Otsu, Shiga Prefecture, had made social media posts last month that could be interpreted as expressions of dissatisfaction with his probation, according to police sources.

Multiple posts decrying the probation system were found on X, formerly Twitter, which were made via an account believed to belong to the suspect, Kohei Iitsuka.

Shiga Prefectural Police believe that Iitsuka, 35, may have carried out a premeditated attack against Hiroshi Shinjo, 60, out of dissatisfaction with his probation. Iitsuka was under Shinjo’s supervision after being given a suspended jail sentence over the robbery of a convenience store.