Blanka Kaczorowska was only sixteen when Nazi Germany invaded Poland in September 1939. She soon joined the Polish underground and was awarded the Cross of Valour on the order of General Stefan Rowecki, commander of the Home Army.

But Kaczorowska ultimately betrayed the resistance she had once served. Together with her husband Ludwik Kalkstein, she passed information about underground members to the Gestapo and became registered as German agent V-98. Their network was implicated in the betrayal that led to Rowecki’s arrest in Warsaw in June 1943.

After surviving the war under German protection, Kaczorowska was arrested in communist Poland in 1952 and convicted of collaboration with the Nazi occupier. While imprisoned, she became an informer for the communist security apparatus and continued working for it after her release.