Kathy
Here is 645 records from the Provost Marshal files on Pettis County. I did not find anything in here on William but it is interesting reading. It gives some insight as to what was going on in Pettis County.

http://www.sos.mo.gov/archives/provost/results.asp?txtName=&radSearch=BEG&txtKeyword=&selCounty=Pettis

Still looking,
Elmer