The head of the public security department of the Osaka High Public Prosecutor's Office was arrested April 23 for allegedly being entertained to the tune of 280,000 yen by mobsters in return for providing internal information.

The arrest of 58-year-old Tamaki Mitsui reportedly came just before he was to allege in public that his fellow senior prosecutors were widely skimming research funds for private expenses.

On the day of his arrest, he was to have met a TV journalist for an on-the-record whistle-blowing interview, according to reports.