Felix Leech was Cyrus Redblock's holographic henchman, who shot a real crew member after the holodeck safeties failed.
Felix Leech was a hired gun working for the gangster Cyrus Redblock in the Dixon Hill story Picard ran in The Big Goodbye. He was waiting in Hill's office for Picard and demanded an object he believed Jessica Bradley had given the detective.
Because a Jarada scan had disabled the holodeck safety protocols, Leech's gun was truly dangerous, and he severely wounded the ship's historian, Whalen. He later joined Redblock in holding the group hostage, and like his boss he walked out of the holodeck and dissolved. Harvey Jason played him.