Osaka Prefectural Police officers falsified reports on a man who assaulted a senior cop at a police station and they committed perjury during his trial, investigative sources have alleged.

The sources said the reports concerned an incident in which the 40-year-old man, a drug suspect, was arrested for obstructing the officer at the police station in Sakai, Osaka Prefecture.

The man, held on drug charges last Dec. 2, allegedly hit the senior officer who was trying to separate him from other detainees and take him to a separate, protective room after he began shouting in a detention cell.