Olympus has announced it is suing 19 current and former executives over one of the biggest scandals in Japan's corporate history.
The Japanese camera maker is demanding millions of dollars in compensation.
The scandal blew open in October last year when Michael Woodford from Britain was abruptly sacked after barely six months as chief executive and president, the BBC reports.
Mr Woodford then went public with his concerns about large and unusual takeovers made by Olympus.
The company at first denied any wrongdoing, but later admitted it had been covering up $US1.7 billion in investment losses dating back decades.
Japanese police, prosecutors and regulators are investigating, as are the authorities in Britain and the United States.
The case will focus on current and former board members, including ex-president Tsuyoshi Kikukawa, former vice-president Hisashi Mori and auditor Hideo Yamada.
Current president Shuichi Takayama will step down in January over his involvement in the scandal, Kyodo News reports.
Olympus spokesperson Satoshi Ikuta also confirmed that all board members subject to the lawsuit would be stepping down in March or April.
Shares in Olympus have lost nearly 60% of their market value since the scandal broke.