A heavily redacted police report has deepened the mystery surrounding the death of a young Chinese semiconductor researcher at the University of Michigan, who took his own life soon after what US federal agents described as a routine and voluntary interview. On the cold morning of March 18, Wang Danhao, 31, spoke with two Department of Homeland Security (DHS) officers for about 10 minutes outside his rented home in Ann Arbor. When one officer offered to end the interview because of the weather,...