I did some more research and found a Lederer family from Germany. Frederich Lederer was Jewish and married a christian woman.
I have photos of the gravestone of Frederich Lederer. Buried in St. John's Lutheran Church Cemetery on Mequon Road and Port Washington Road in Mequon, WI which is not far from Thiensville and Cedarburg. Thiensville was once the county seat for these areas. Now it is in Whitefish Bay or at least some records are.