Johnny

From Memory Alpha, the free Star Trek reference.

Johnny was a character in Picard's Dixon Hill holoprogram. He was holding Hill at gunpoint, when Guinan who was playing the role of Gloria, came to Hill's office. Hill said that she was his cousin. Johnny did not believe him and asked if Gloria knew where his money was. He said that Hill had stolen his money. He was killed as he walked past a window by machine gun fire. (TNG: "Clues")

Credited as "Gunman" and played by Thomas Knickerbocker. Christopher Doyle served as his stunt double.