Cannon and her husband had at least one daughter, who twice married men known to engage in slave-stealing and kidnapping. The daughter first married Henry Brereton, a blacksmith who kidnapped free Black Americans for sale into slavery. Brereton was convicted and imprisoned in 1811 for such kidnapping, but escaped from the Georgetown, Delaware jail. Brereton was captured, convicted of murder in another case, and hanged with one of his criminal associates, Joseph Griffith. Some time after this, Cannon's daughter married Joe Johnson, who became the mother's most notorious partner in crime. Johnson had a tavern a few miles from the Cannon house. Information about Cannon and Johnson has been confusing, with fact and fiction mixed; Johnson has been described as Cannon's husband or son-in-law. The Cannon–Johnson gang included whites and blacks, among them Henry Carr and John Purnell, described as a "yellow" man or mulatto, who used several aliases. They served as decoys to get young blacks aboard their boat or close enough to take captive. Robert Bereton, a relative of Cannon's late son-in-law, also continued to be involved with the gang at least until 1826. Political and economic excuses for slaves The U.S. Congress banned the importation of slaves in 1808. Because of demand due to development of cotton culture in the Deep South and the spread of short-staple cotton made profitable by invention of the cotton gin, the domestic slave trade became even more lucrative. The cash value of slaves shot upward, creating a strong incentive for kidnappers. By this time, many free Black Americans lived in Maryland and Delaware, which were still slave states, as a result of manumissions after the Revolutionary War, in addition to mixed-race families formed by unions between free white women and African men in colonial Virginia. In addition, nearby Philadelphia, Pennsylvania had the largest population of free black Americans in the North and no professional police force in the antebellum years. Residents, especially children because they were more easily controlled, were at risk from kidnappers. At a time when southern slaveholders came to the city with their slaves, it was difficult for onlookers to determine what was happening between adults and children, and especially between adult black Americans and those who appeared to be their children, when kidnappers used black accomplices. Cannon's kidnapping forays could troll waterfront areas throughout the region, enticing young men aboard their boat to help decoy workers. The