Help! I am trying to trace my Eisenmann ancestor's, but I am having no luck.

My grandmother (Ida (Andersen) Eisenmann) once told me a story regarding my g grandfather. According to my grandmother, his name was Charles Eisenmann. He made his living fishing on Lake Michigan and was robbed and murdered one evening upon returning to shore with his catch. He was married to Theresa (I do not know her maiden name, but my grandmother believed she was born in France (?)). Theresa remarried several times after Charles's death - once to a Dr. Shoemaker, a Jones, a Hollinback, and a Lippett (I am not sure if the spellings are correct). Charles and Theresa had a least one child my grandfather, John Godfrey Eisenmann born July 8, 1912 in Beloit, Wisconsin. My grandfather had brothers and sisters but I don't know names or who fathered each of the siblings.

I would really appreciate any info or if anyone is able to confirm or deny the above story.

Thank you in advance