Even worse, during the intermission Parker went out for drinks with the coachman and footman of Lincoln's carriage. He was not at his post when John Wilkes Booth entered the president's box.
Was Parker ever implicated in Lincoln's murder? Did he lose his job after this? What sort of employment record did he have before he received this prestigious assignment of guarding the president?
You can find the surprising answers in Paul Martin's article, "Lincoln's Missing Bodyguard," on the website for Smithsonian magazine.