Sometimes, the way to unravel a secret is very simple, but it is almost impossible before finding the correct approach. And according to the current information, Leonard and his team successfully found that crucial key.
Based on public information, this man named Hans had been working as a warehouse keeper in a machinery processing factory in Dresden until he retired, and his overall life didn't seem much different from that of countless workers at the time.
According to records, he never married and had no relatives. Considering the casualty rates of Germans in World War II and Hans' personal situation, this was not such a strange thing.
But now, in Leonard and Joan's eyes, another possibility for Hans' situation is to avoid having his secret discovered since more people would mean more risk of exposure.