Hong Kong (CNN) -- Brothers Thomas and Raymond Kwok, who control Hong Kong's biggest property development company, Sun Hung Kai, have been arrested for suspected corruption, authorities said Thursday.
Also arrested for suspected corruption was a person described by Hong Kong's Department of Justice as "a former principal official of the government of the Hong Kong Special Administrative Region," a spokesman for the Independent Commission Against Corruption said.
The Kwok brothers' fortune is $18.3 billion, according to Forbes Magazine, which rank the brothers and their family as the 27th richest in the world.
The commission's report said "the arrested persons are alleged to have committed offenses under the Prevention of Bribery Ordinance and misconduct in public office."
The arrests come 10 days after Sun Hung Kai's executive director, Thomas Chan, was arrested by the commission in connection with a bribery investigation.
Four other people, whose backgrounds weren't disclosed by authorities, were also arrested on corruption charges.
On Thursday morning, Sun Hung Kai Properties suspended trading of its shares. The company has since announced the shares will resume trading when Hong Kong's stock exchange opens Friday morning.
The firm has set up a special committee to handle all matters arising from the investigation, and the company's board, whose six members include the two brothers, has resolved that the Kwoks will "continue to undertake and discharge their duties to the group, including their duties as joint chairmen and managing directors of the company," according to a company statement.
CNN's Andrew Henstock contributed from Hong Kong and Michael Martinez from Los Angeles.