Crook, the President’s chief bodyguard, was off-duty. In his place, John F. Parker was responsible for the President’s safety. Accounts vary on Parker’s whereabouts at the precise moment Booth entered the box. Some say the President permitted him to take a better seat, thereby leaving Lincoln unguarded. Others say he was in a tavern across the street and wasn’t seen again until around 6 a.m. the next morning.
With no one around to stop him, Booth pulled out his pistol and fired one shot into the President’s head. The bullet entered through his left ear and lodged behind his right eye.
As the President slumped forward, perhaps grasping one of the flags draped in front of him, Major Rathbone struggled with Booth who, using his knife, slashed Rathbone’s arm. Booth jumped from the box but the spur of his boot caught a flag. When he fell to the floor, he fractured his leg.
Undaunted, Booth fled the theater through the back door and escaped on horseback. He crossed the "Eastern Branch" of the river, about ten minutes ahead of fellow conspirator David E. Herold, as he fled to Anacostia. The police blotter reveals Booth was the suspect police would try to find.