John Duff (counterfeiter)

Suspected of being British spies, they immediately took an American oath of allegiance, where Duff and his men joined Clark's Illinois Regiment, Virginia State Forces.

Duff enlisted into Captain John Williams' Company in Cahokia and rose to the rank of sergeant in the Illinois Regiment.

In the mid-late 1780s, Duff was living in Kaskaskia, Illinois and was in business with two brothers of the captain of the Ohio County, Virginia Militia and Revolutionary War Patriot, Samuel Mason who later became the notorious river pirate.

Daniel McDuff owned slaves while residing in Kaskaskia, as was the custom of transplanted Southerners and the French creole population in the Illinois Country.

After 1790, John Duff was associated with the South Carolina counterfeiter, Philip Alston, the Virginia river pirate, Samuel Mason, and the North Carolina serial killers the Harpe brothers, at Cave-in-Rock, in the U.S. Northwest Territory, where he learned the illicit business of counterfeiting, known as "coining", where he could make a lot money in criminal pursuits.

On June 4, 1799, a group of three Shawnee Indians and a French courier du bois were hired by U.S. Army officer, Captain Zebulon Pike, Sr., father of the explorer Zebulon Pike, who was the commandant at the frontier outpost Fort Massac, now Metropolis, Illinois.

Private John Duff served in the, ranks of, George Rogers Clark 's Illinois Regiment , walking through chest-high, icy water, on the march to Vincennes , January 1779, in a painting, by Frederick Coffay Yohn
In the 1790s, John Duff and his criminal associate, Philip Alston , carried out their counterfeiting operation, in the relative seclusion of the wilderness, at Cave-in-Rock
Fort Massac , down river , from Cave-in-Rock , where, in 1799, the U.S. Army commandant, Captain Zebulon Pike, Sr., father of the explorer , hired three Shawnee Indians and a French courier du bois , to hunt down and kill John Duff.