The post had long lacked the means of enforcing its own stringent laws, particularly regarding the theft of money from the mail. Such robberies had only increased as the population grew; immigrants and a decline in old-fashioned agrarian values were customarily blamed. . . . Determined to change that status quo, McLean increased the post’s surveillance capabilities and cleared the way for the establishment in 1830 of the Office of Instructions and Mail Depredations, the department’s investigative branch.