The estranged brother of two Hong Kong billionaire property developers ensnared in a high-profile anti-corruption probe has been arrested as part of the investigation into alleged bribery. Sun Hung Kai Properties Ltd. said Friday that Walter Kwok, who is a non-executive director of the company, was arrested by anti-corruption police on Thursday night and later released on bail. Walter Kwok’s brothers, Raymond and Thomas Kwok, along with a former senior government official were arrested briefly in March by the Independent Commission Against Corruption. They have not been charged.—AP