Anti-graft officers have arrested another suspect in connection with a bribery scam in which a syndicate generated a profit of more than HK$100 million through the fraudulent trading of warrants over the past two years. The arrest has brought to 30 the number of people arrested over the past two days in the operation, codenamed 'Night Sun'. Investigations are continuing. The man who was arrested late on Thursday night was alleged to have helped to open accounts used by the syndicate for its trading operations, a government source said. He was still being held for questioning last night. The director of an investment company - the alleged mastermind of the syndicate - four traders from four derivative warrant issuers, six securities brokers, and 18 alleged associates, who were arrested on Wednesday and Thursday, had been released on bail and no one had been charged, the Independent Commission Against Corruption said. The ICAC said the ringleader allegedly offered bribes to the warrant traders in return for favourable prices, which allowed him to earn profits by selling at higher prices in the market via the syndicate. Investigations revealed that the daily trading volume was estimated to range from more than HK$10 million to more than HK$100 million, the anti-graft watchdog said. During the operation, graft busters seized suspected bribe money of more than HK$2 million. The ICAC started the investigation after a corruption complaint. The arrests were the first related to warrants in Hong Kong, which has the world's largest market in the popular stock derivative.