Researchers from the Polish Institute of National Remembrance started their investigation at the Victoriaschule building in Gdańsk, North Poland, where Polish citizens were detained and murdered by Gestapo in 1939 and the communist regime secret police in 1940s-50s. So far they found walled up and filled in corridors in the basement.
In 1939, right after the invasion of Poland, German army has organised a transition camp for civilian prisoners, mostly Poles from Gdańsk, in the building. The camp functioned until September 15th having around 3000 people come through it. The Germans humiliated and tortured many of the detained during interrogations. Some of the arrested were sentenced to death, and others were sent to concentration camps, mostly KL Stutthof. During the war the building serves as a school for girls, and near the end of war was turned into a military hospital. As the Russian Army took over Gdańsk in 1945 the building survived mostly undamaged. After being rebuilt and renovated it became the seat of the local communist secret police. Since 1947 the building housed their offices and a temporary prison, where people arrested for political reasons were once again tortured and humiliated. Right before the building was passed by them to a teacher seminar in 1957 a decision was made to fill the basements, where the cells were, with rubble.
Now, historians and researchers have taken the effort to investigate the rubble-filled basements in order to discover and reach the rooms where the cells were. They found out that the basement is not only filled with rubble but also it was covered with concrete. So far the researchers have used non-invasive techniques conducting a survey with GPR (ground penetrating radar) and checking available spaces with cameras. So far an area of around 250 square metres has been explored, revealed some unknown rooms. Some of them seem to have been filled with rubble right after the war when the area was cleared, but some clearly were filled in the 1950s and masked with concrete. In the near future the researchers plan to drill holes and remove to rubble to investigate the individual rooms.