While researching General Alexander Posey, it turned out that Posey's father, Thomas, who died in 1818 in Shawneetown, Gallatin Co., Illinois, years before the start of the Black Hawk War, loomed large. General Thomas Posey, Alexander's father was also the father-in-law of Joseph M. Street, a Winnebago Indian agent in the midst of the Black Hawk War.
Page 95: "His (Nicholas Boilvin's) place as Indian agent at Fort Crawford was filled by the appointment of Joseph Street, a general in the Illinois Militia." [Twilight Of Empire]
Black Hawk was seized on August 25, 1832, and delivered to General Street, which signaled the end of the Black Hawk War.
It was in this article, in the Milwaukee Sentinel, dated May 19, 1907, entitled "Romantic career was Gen. Street's," where I first read that General Joseph Street's father-in-law, Thomas Posey, was considered by many to be George Washington's natural son! Additional information about a possible familial connection between Posey and Washington can be found here, here and here.
Another surprise ending while researching.