Japanese prosecutors have raided the headquarters of camera and medical equipment maker Olympus as part of an ongoing investigation. Olympus is being probed over its accounting practices and the admission that it hid losses. The issue came to light after former chief executive Michael Woodford claimed he was fired for questioning payments relating to mergers. Olympus admitted it hid losses of $1.5bn (£968m) over past two decades. New twist\' Last week Olympus filed its revised earning reports with the Tokyo Stock Exchange. In its latest accounts for the six months to the end of September the company declared a loss of 32.3bn yen ($414m; £267m). It also revised down the value of its net assets to just 46bn yen, down from the 225bn yen it stated in March 2007. Analysts said the raid on its headquarters just days after the filing of the report was a significant development. \"I would suspect that any documents needed by the prosecutors could have been just requested for and delivered by Olympus,\" Martin Schulz of Fujitsu Research Institute told the BBC. \"But the fact their offices have been raided seems to indicate that there are new developments in the investigation that might add a new twist to the story,\" he added.