By Céline Le Prioux, AFP

A picture of German lecturer Felix Puelm’s grandparents Paul and Brigitte, a small picture of Paul in army uniform, their marriage certificate and a copy of a National Socialist German Workers’ party (NSDAP) membership card, found in an online database published by Die Zeit.

Many German families have faced the uncomfortable question: What did grandpa do during the war? Now, the answer may be just a few clicks away - but it may not be what they wanted to hear.

In March, the US National Archives posted online the digital scans of roughly 12 million membership cards from Adolf Hitler's Nazi party.

The records, seized by American troops after the Nazis were defeated in World War II, had previously only been available on microfilm.