Investigators are searching for clues that could help them identify the masked gunman who stalked and killed the leader of one of the largest U.S. health insurance companies on a Manhattan sidewalk, then disappeared into Central Park.
UnitedHealthcare CEO Brian Thompson, 50, died in a dawn ambush Wednesday as he walked to the company's annual investor conference at a Hilton in Midtown, blocks from tourist draws like Radio City Music Hall and the Museum of Modern Art.
