In case it's helpful to your research, there were family death notices published in the local German paper for an Annie Jane Baas, née Treutelaar in 1924. Other Baas names found in these papers include an Abram, Charlotte, E. C., Emilie, Ernst, Isaac Sr., & John G.
Indexing of these papers started in 2007 and continues today.
Gary Rebholz, compiler/editor
"Milwaukee's German Newspapers; an index of death notices and related items" (1844-1950).