Daewoo Shipbuilding offices raided in South Korea
South Korean prosecutors have raided Daewoo Shipbuilding and Marine Engineering as part of an investigation into alleged accounting irregularities.
It comes after an audit committee requested a probe into two of DSME's former chief executive officers over possible mismanagement.
The world's second-largest shipbuilder has been trying to raise money to reduce its debts.
The firm posted its biggest net loss of 3.19tr won ($2.8bn; £1.9bn) last year.
DSME and South Korea's two other biggest shipbuilders, Hyundai Heavy Industries and Samsung Heavy Industries, have all been hard hit by the slump in oil prices and global economic slowdown.
They have struggled with reduced demand for tankers and container ships and have had to delay projects in offshore drilling and production.
They are also facing rising competition from Chinese shipbuilders.
According to reports, 150 officials went to DSME headquarters in Seoul and one of its shipyards on the island of Geoje.
Computer hard drives, accounting books and documents were seized by officials, who are looking into whether it manipulated its 2013 and 2014 financial statements.