Surveillance video shows when Thompson appeared, the suspect stepped behind him and opened fire from close range, striking him in the back and leg. Police said the gunman's weapon appeared to jam, but he still managed to continue firing.

Mr. Thompson managed a division that employs about 140,000 people and offers insurance plans to employers and individuals.

Brian Thompson, the CEO of UnitedHealthcare, who was fatally shot in Midtown Manhattan on Wednesday in what New York police called a “brazen, targeted attack,” was a longtime leader in Corporate America,