How did the people that killed Jesse die?

Jesse James was killed by Robert Ford, a member of his gang, who shot him in the back of the head on April 3, 1882. Ford was later shot and killed in 1892 by Edward O'Kelley, who sought revenge for the murder of James. O'Kelley himself died in a gunfight with the law in 1902. Thus, the circle of violence continued, leading to the deaths of those involved in Jesse's assassination.