The international police agency Interpol announced Sunday that its missing president had resigned "with immediate effect" after China said the man was under investigation over unspecified legal violations and his wife told reporters that he had texted her an image of a knife, leading her to believe he was in danger. Grace Meng told reporters that she had not heard from her husband, Meng Hongwei, since Sept. 25. That day, he sent her the knife image from an Interpol phone four minutes after sending an initial message saying, "Wait for my call." She said the call never came and she...