South Korean prosecutors Tuesday raided the offices of Daewoo Shipbuilding & Marine Engineering Co. to investigate alleged accounting irregularities.

The move comes after an audit committee requested a probe into two of Daewoo Shipbuilding’s former chief executive officers over possible mismanagement of the company.

The world’s second-largest shipbuilder posted its biggest losses last year after reported write-offs for delayed projects. The net loss posted was 3.19 trillion won ($2.8 billion). It has been trying to raise money to reduce its debts after deliveries of offshore drilling and production units were pushed back. The main reason for this has been the fall in oil prices that crushed demand over the past two years, Bloomberg reported.

According to the BBC, 150 officials went to Daewoo Shipbuilding headquarters in Seoul and one of its shipyards on the island of Geoje. They reportedly seized computer hard drives, accounting books and documents in order to look into whether its 2013 and 2014 financial statements were manipulated.

Bloomberg reported that the Seoul Central District Prosecutors’ Office said it could not comment on any ongoing investigation.

Daewoo Shipbuilding, along with South Korea’s Hyundai Heavy Industries and Samsung Heavy Industries, is facing increased pressure due to the oil slump combined with rising competition from Chinese shipbuilders.