[zozbot234]

Making an Anne Frank game while also praising "Adolf Hitler's bolstering of Nazi Germany in the 1930's" is pretty unambiguous, I'd say. Nothing that a random 8chan user couldn't have come up with "for the lulz" of course, but that website has also been associated with violent acts.

[BryantD]

Huh. That honestly struck me as irony, given that it’s in conjunction with his grandmother’s departure from Germany. But I do see your point.

Note that the dates may not be accurate; according to a quick bit of genealogical research, his grandmother Paula married his grandfather in Bavaria in 1955 < https://www.genealogy.com/ftm/b/i/s/Robert-S-Bishop/BOOK-000...>. Could also be that she left Germany and then returned for the wedding, of course.

Paula’s mother’s surname appears to have been Ketzler, which doesn’t tell us a ton about ethnic background. Not that it would tell us much about the attacker in any case, even if that was why she left Germany.

Edit: he had at least a bit of 4chan activity, as per his journal.