The co-chairmen of Sun Hung Kai Properties have had further criminal charges laid against them in the latest twist to the corruption case involving former chief secretary Rafael Hui Si-yan. In an amended indictment, the prosecution yesterday pressed two additional charges against Raymond Kwok Ping-luen - a bribery charge and a count of conspiracy to commit misconduct in public office. He now faces four charges. His elder brother, Thomas Kwok Ping-kwong, was charged with an extra count of bribery, taking to three the number of charges against him. Under the amendment, their names were added to existing charges that had been filed against the other defendants - Hui, SHKP executive director Thomas Chan Kui-yuen and former Hong Kong Stock Exchange official Francis Kwan Hung-sang. The additional bribery charge against the brothers alleges that the five conspired to offer more than HK$11 million to Hui to induce him to remain favourably disposed to SHKP. The charge, an offence under the Prevention of Bribery Ordinance, covers the period between June 30, 2005, and January 20, 2009, when Hui was chief secretary and a member of the Executive Council. The extra count against Raymond Kwok alleges all five conspired to commit misconduct in public office when Hui allegedly committed misconduct as chief secretary by being favourably disposed to SHKP and its subsidiaries in return for HK$8.5 million. Hui, 68, faces eight charges, including misconduct in public office, conspiracy to commit misconduct in public office, furnishing false information and conspiracy to offer an advantage to a public servant. Hui allegedly received about HK$28.8 million in cash, HK$5.4 million in loans and the rent-free use of two luxury flats in Happy Valley between 2000 and 2009. In a stock exchange announcement, SHKP said the case had not and would not affect its operations. "Business continues as usual," it said in the statement. "SHKP has been managed under the collective leadership of the executive committee and maintains high standards of corporate governance." The trial, expected to last 70 days, is scheduled to begin on May 8.