Dear Mr. Doerr,
First thing first. 
Thank you for easy access to Kennedy's 1860 City Directory.
Perusing... noted the following...
Zakrzewski Herman, machinist, r. 290 N. 7th [Berlin native G-G-father of Bob Doerr]
Not positive of pronounciation/spelling...
Might Zakrzewski be pronounced something like....
Za..cress....ski..??
Warmest Regards,
Barbie Lew
P.S. Does the given name Rita ring a bell with you?