BEIJING: Executives at one of China’s largest copper trading houses have lost contact with the company’s founder and believe that he has been detained by police for questioning, according to people familiar with the matter.He Jinbi founded and built Maike Metals International Co into China’s biggest importer of refined copper before a liquidity crisis last year brought the company to its knees. Colleagues haven’t heard from him for at least a day, and have been informed that he was taken away by police for interviews in his home...