Prosecutors at the Manhattan District Attorney's Office have begun presenting evidence to a grand jury as they work to secure an indictment against Luigi Mangione.

Who is Brian Thompson? Everything we know about the UnitedHealthcare CEO and his murder in New York City - Luigi Mangione allegedly kept a notebook that laid out his plot to ‘wack’ Thompson at his ‘pa

Here's what we know about UnitedHealthcare CEO Brian Thompson, who was shot to death in Manhattan on Wednesday, Dec. 4.