From St Charles Missouri: a Brief History, by James W Erwin, pg 106
"On their first scout, troops under Captain Henry Windmuller killed 2 civilians and wounded 2 others who were working peacefully on their farms. About a week later, Kreckel refused to send troops to ambush rebels reportedly camped on a farm owned by Henry Renoe because he feared it a "secesh trick". Two days later Windmuller led a patrol to the farm....ransacked the house... shot Renoe on the way back to Fulton."
Of course I can't see a primary reference.