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.

Brian Thompson was laid to rest at a private funeral service in his Minnesota hometown on Monday. That same day, Luigi Mangione was arrested in Pennsylvania and charged with murder in connection to the UnitedHealthcare CEO’s death.

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