Brian Thompson led one of the biggest health insurers in the US but he was largely unknown to the millions his decisions affected

Brian Thompson, the CEO of United Healthcare, was killed by a masked gunman outside a hotel in City where he was expected to speak to a ballroom full of colleagues, officials said.

Calling the incident a “brazen targeted attack,” police said the suspect was waiting for Thompson before shooting him outside of a hotel in Midtown Manhatten. But while authorities stressed that the killing was “premeditated” and planned, the motive for the shooting is still unknown.