He’s trying to cover his tracks getting ready for his case. Probably had his lawyer or a family member delete it since he doesn’t have access.
“In Japan, court cases can take anywhere from several months to several years, depending on the type and complexity of the case. At the district court (the court of first instance), the average duration is about 10.5 months for cases that settle, and 14.6 months for those that end in a judgment with the defendant's appearance. Appeals to the High Court can take from several months to two years, with the length of time often correlating with the length of the original district court trial.”