A few years back I'd hoped to find the origin of the song. I doubt I'll ever learn it for sure. Some are convinced it came from the race riots in East St. Louis of 1917. Others maintain it goes back to "King Brady" in a series of dime novels in New York in the 1890s.
It seems that most versions from the 1950s on are derived from Lead Belly's interpretation in the 1940s. One of the more interesting versions is that of Joel Mabus, based on one of the versions in the Sandburg book of 1927. His lyric can be found at www.joelmabus.com