Wohlgemuth gravestone in Stargard

At Virtual Shtetl, there are photos of the destroyed Jewish cemetery of Starogard Gdansk. Just a few headstones are intact, but see here the one for a Wohlgemuth woman buried in 1890. She could be an aunt by marriage of Isaac's father Leopold. 

The Nazis killed very few Jews in Starogard for the simple reason that almost everybody had left the town before 1939. The Jewish population of Starogard peaked at around 600 in 1875, when Isaak was a boy, and then began to decline for economic reasons. We know that Isaak left there for Elbing at a time that many young people were leaving shtetl life for larger cities. 

There was an atrocity in the fields outside of Starogard, but they were Poles that were gunned down, not Jews. The Nazis occupied the synagogue building after 1939. The building is still standing (see the photo), having been used by merchants for many years, but was recently returned to the Jewish Community of Gdansk.

Also here is four-minute video shot at the Starogard cemetery. The narration is in Polish but images and music are quite moving. I believe I see another Wohlgemuth headstone in the video.
http://www.sztetl.org.pl/en/video/63/