Keywords: PinkLinkMc alternate.jpg Allan Pinkerton President Abraham Lincoln and Major General John A McClernand This photo was taken not long after the Civil War ™s first battle on northern soil in Antietam Maryland on October 3 1862 Pinkerton was the head of Union Intelligence Services at the time He also allegedly foiled an assassination attempt against Lincoln His wartime work was critical in Pinkerton ™s development which he later used to pioneer the American private detective industry when he formed the Pinkerton National Detective Agency LOC-image cwpb 03525 1862-10-03 Creator Alexander Gardner <gallery> File PinkertonLincolnMcClernand jpg </gallery> PD-Old-100 Pinkerton Lincoln and McClernand by Alexander Gardner |