Rudiger,
On website wwiimemorial.com there's an entry for 1st Lt. John (Jhon?) A. Wenner, 0-810609 from Hamilton County, OH.
Cause of death is given as FOD (finding of death) instead of KIA.
I believe this means that his death was only recorded later because the actual cause and/or date could not be established at that time by the Americans.
He's not mentioned on the MIA list (see
http://www.dtic.mil/dpmo/worldwarii.htm) and so far haven't been able to locate a gravesite (yet).
Regards,
Leendert