nine
o'clock
A curious crowd gathered about the premises of Lamb and Drummond on Pall Mall , to gaze at the now vacant window , and the services of a policeman were required to keep the sidewalk clear . Many persons recalled the similar case , some years before , of the Gainsborough portrait of the Duchess of Devonshire . Mr. Lamb , it appeared , had been detained at his place of business until long after the closing hour , writing important letters . 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 .