This incident is covered briefly on pages 69-70 of the book I mentioned in the original reply. The text notes the incident was debated in the rival Missouri Republican and Missouri Democrat newspapers for June 18th. These appear to be the sources used by Winters [the former gleaned secondarily from Scharf "History of St. Louis City and County" pp. 523-24] for his section dealing with the shooting on the 17th. Also, an article appeared in Leslie's Illustrated Newspaper, June 29.