The Germans were afraid that their extermination activities would be uncovered by the approaching Red Army. Therefore, in 1944 they started removing the traces of the crime, in accordance with a directive from Reichsführer-SS Heinrich Himmler. Works executed in the forests near Piaśnica Wielka consisted in recovering bodies from mass graves and burning them on piles prepared nearby. Inmates were brought from the Stutthof concentration camp to perform the task. As the Germans were afraid the inmates would flee, their put their legs in fetters. The smoke and the smell of burning bodies reached Piaśnica Wielka, Domatówko, Warszkowo, Leśniewo and other villages in the vicinity. Throughout the time of works, which lasted for about 6 weeks, the inmates slept on the ground covered with a thin layer of straw. After the task was completed, they were killed and their bodies were burned.
No German documents pertaining to the organization of the massacre in Piaśnica have been preserved. Because of all the actions taken with the aim to remove its traces, it is very difficult today to determine the size and circumstances of the mass executions carried out in the forests near Piaśnica Wielka.