China Evergrande Group's shares dropped 25% after police detained staff at its wealth management unit, raising concerns about a new investigation that could worsen the company's existing crisis. Evergrande, the world's most indebted property developer, has been at the center of a real estate sector crisis in China, causing global market concerns. The exact details of the police action and the charges are unknown. Evergrande reported a net loss of 33 billion yuan ($4.5 billion) for the first half of the year and has delayed its decision on offshore debt restructuring.