were overwhelming odds were unduly cautious, causing him to avoid offensive actions almost completely in favor of siege warfare and taking a defensive posture. This led to his retreat in the Peninsula Campaign, his failure to crush Robert E. Lee's Army of Northern Virginia at the Battle of Antietam, and his unnecessary delay in carrying out his orders to pursue Lee's army as they retreated from their invasion of Maryland back into Virginia. These actions were all based on McClellan's firm trust of Pinkerton's reports, although the problem was compounded by the intelligence-gathering ineptitude of Brigadier General Alfred Pleasonton, McClellan's head cavalryman and his alternate source of enemy troop information when Pinkerton did not have agents in place. After the war Following Pinkerton's services for the Union Army, he continued his pursuit of train robbers, including the Reno Gang. He was hired by the railroad express companies to track outlaw Jesse James, but after Pinkerton failed to capture him, the railroad withdrew their financial support and Pinkerton continued to track James at his own expense. After James allegedly captured and killed one of Pinkerton's undercover agents (who was working undercover at the farm neighboring the James family's farmstead), he abandoned the chase. Some consider this failure Pinkerton's biggest defeat. In 1872, the Spanish Government hired Pinkerton to help suppress a revolution in Cuba which intended to end slavery and give citizens the right to vote. If Pinkerton knew this, then it directly contradicts statements in his 1883 book The Spy of the Rebellion, where he professes to be an ardent abolitionist and hater of slavery. The Spanish government abolished slavery in 1880 and a Royal Decree abolished the last vestiges of it in 1886. Personal life Pinkerton secretly married Joan Carfrae (1822–1887), a singer from Duddingston, in Glasgow on March 13, 1842. They remained married until his death. Death Pinkerton died in Chicago on July 1, 1884. It is usually said that Pinkerton slipped on the pavement and bit his tongue, resulting in gangrene. Contemporary reports give conflicting causes, such as that he succumbed to a stroke – he had a year earlier – or to malaria, which he had contracted during a trip to the Southern United States. At the time of his death, he was working on a system to centralize all criminal identification records; such a database is now maintained by the Federal Bureau of Investigation. Pinkerton