Looking for Death Records of Minnie Rathke Lentz

My Grandfather was Frank Lentz. He married Minnie Rathke in Milwaukee, Wisconsin on August 10, 1907.

Minnie was the daughter of Fred Rathke and Bertha Riebe Rathke. Minnie died approximately one year after they were married. I have been unable to find death records on her. I also do not know if Minnie was her real first name or if she was actually a Wilhelmina! She is listed as Minnie on their marriage certificate.