German Evangelical Cemetery is not in Detroit. It is located in
Barry County,
Michigan not far from
Battle Creek.
Another possibility as to where your ancestors may be buried is Ann Arbor, MI which is much closer to Detroit than
Battle Creek. Years ago, and some people even today, say they are from Detroit, when they in fact are from an area close to Detroit like Ann Arbor.
My guess is there may have been a name change to the cemetery. I mention Ann Arbor because it had a HUGE
German population beginning about 1829 and continued for about 100 years.