Dentsu Inc., Japan's leading ad agency, has been summarily indicted for suspected labor violations after the suicide of a new recruit focused attention on its culture of overwork and prompted a criminal investigation.

Three senior officials who allegedly made employees work illegally long hours, however, will not be indicted, the Tokyo District Public Prosecutor's Office said Friday.

A summary indictment is typically followed by a summary court order requiring the payment of fines, and effectively closes the investigation into Dentsu.