Prosecutors investigating a massive stock manipulation case involving SG Securities Korea are moving to freeze the assets of related figures including the alleged mastermind, Ra Deok-yeon, the head of an unregistered investment consulting firm.

A joint probe team including the Seoul Southern District Prosecutors' Office and financial authorities requested a pre-indictment preservation of assets worth some 264 billion won, or nearly 200 million U.S. dollars, belonging to Ra and his associates last Friday after he was formally arrested the previous day.

Court approval of the request will result in the freezing of financial accounts and the barring of asset disposal by key suspects.

Based on the evidence gathered so far, prosecutors suspect Ra and others illicitly accrued 264-point-two billion won through stock manipulation, half of which was categorized as commission fees.

Officials tracking down their real estate and financial holdings found that Ra had purchased properties overseas including a golf course, and planned to retrieve the criminal proceeds in cooperation with law enforcement agencies abroad.

After Ra's arrest on Thursday, arrest warrants were also issued for two of his close aides on Friday.