His Perryville residence adds another avenue of research. Unless my memory is failing me, I recall that most wartime copies of the Perryville Union newspaper still exist. Your library can probably get the microfilm from the State Historical Society of Missouri in Columbia. Denezet would have been one of the first hometown boys killed in the war. Since the specific date of death is not certain, I'd suggest scouring all of the newspaper issues for September and October 1861. Might be a story on the skirmish and/or the death, or maybe a letter to the newspaper from one of the soldiers from the 11th Missouri. Published letters to the newspaper were fairly common, especially in the early days of the war. Just to cover your bases, you might also check to see what other newspapers in the area at the time have issues from the time period preserved on microfilm. The Historical Society will have a list.