“With enough in my pocket now to last me a month, I gave the town a thorough canvassing for something worth while. I found many places that appeared to be advertising for a bursar and the most promising was the big general store. It was packed to the roof with merchandise, and the owners, to save floor space, had placed the safe behind the stairs, where it could not be seen from the street. I ‘pegged’ the spot for a week and satisfied myself that after the was closed at night no one entered it till opening-up time in the morning.

The expression, ‘I have him pegged,’ which has crept into common usage, is thieves’ slang pure and simple, and has nothing to do with the game of cribbage as many suppose. The thief, to save himself the trouble of staying up all night watching a spot to make sure no one enters after closing hours, puts a small wooden peg in the door jamb after the place is locked up. At five or six o’clock in the morning he takes a look. If the peg is in place the door has not been opened. If it is found lying in the doorway, that means somebody has opened the door in the night. If he finds the place is visited in the night he must then stay out and learn why and at what time and how often. He now has the place ‘pegged’ and plans accordingly or passes it up as too tough.” – You Can’t Win by Jack Black