four o'clock in the morning
He left at nine o'clock , and Raper , the night watchman , fastened the street door behind him . During the night the policeman on duty in Pall Mall saw or heard nothing suspicious about the premises . The Rembrandt was on an easel in a large room back of the shop proper , and from it a rear door opened on a narrow paved passage leading to Crown Court ; the inmates heard no noise in the night . At four o'clock in the morning a policeman , flashing his lantern in Crown Court , found a window open at the back of Lamb and Drummond 's premises . He entered at once . Inside the gas was burning dimly , and the watchman lay bound and gagged in a corner , with a strong odor of drugs mingling with his breath . The Rembrandt had been cut out of its frame and carried away .