At the beginning of the camp’s functioning, it was mainly Poles, residents of the Sokołów county, who were sent here. From the autumn of 1941, residents of the remaining counties of the Warsaw district began to be put here. Since 1943, the camp officially served as a penal camp for the population of the Warsaw district, mainly from its eastern part. Initially, Poles were sent to the camp on the basis of a decision of the administrative authority, i.e. the mayor. As a rule, such a decision was not delivered to the convicted person, but was addressed directly to the commandant, at the same time bringing the convicted person, who in principle was not informed about the date of the punishment.

In 1941, there was no clear division between Polish and Jewish prisoners. It all changed in 1942. Since July 1942, the number of Jews, mainly professionals and craftsmen, has increased. There were also cases of sending small transports of Jewish prisoners to the labour camp instead of the death camp 2 km away. The main aim was to obtain young, strong men. It was decided to destroy them through hard physical work.

Another way of “replenishing the workforce” was to put in the camp those detained during raids and manhunts organised in various towns, on railway routes and in nearby villages. From April 1942, juveniles up to the age of 18, who were considered criminals by the occupation authorities, as well as people whose main trial was not completed for some reason, were sent to the camp. Forced labourers from the Reich who had left their place of work or had not returned to it after using a pass were also detained here. They were the so-called “perpetuals”, i.e. persons without a fixed date of release and used for heavy work. The officers of Bahnschutz – a railway security force, and Werkschutz – a factory security force, who were of Polish descent and during the period of service committed an abuse, mainly on criminal grounds, were also imprisoned. They often helped the crew to guard prisoners at work. For some prisoners with a fixed period of time in the camp, the commandant extended their stay for all kinds of offences until the prisoner died of exhaustion. There were also cases in which, after serving his sentence, the prisoner was sent to forced labour far into the Reich.

The procedure for admission to the camp was simple. Individual prisoners or groups of prisoners brought or transported here, as well as those “taken over” from the extermination camp, were sent in front of the commandant’s barrack. Here all the property was taken away from them. Then the prisoners were divided into groups by profession. Those who did not have a profession or were useless in the camp conditions were sent to do simple, but the hardest work. Those unable to work were separated from the others and later killed outside the camp.

Poor hygienic conditions and excessive density in the barracks caused that the prisoners were infested with lice. This contributed to the development of infectious diseases, which, with poor food and overwork, resulted in numerous deaths. In the autumn of 1942, the typhus epidemic broke out. The sick were isolated, and then most of them were shot. The sick prisoners were taken care of by doctor Paciorek. The Germans, afraid of the expansion of the epidemic, directed some of the prisoners to the hospital in Węgrowo. Another disease common among the prisoners was scabies (skin disease). Those who stayed here for a long time were not able to wash themselves thoroughly and wash their clothes. Although there were three wells and two swimming pools in the camp, prisoners were not allowed to draw water on their own. In many memories of those who survived, there is a theme of constant thirst and hunger.

The fixed number of prisoners in the camp is difficult to determine. It can be assumed that 1,000-2,000 people stayed there at one time. The turnover and mortality rate of prisoners in the camp was quite high.

The prisoners were divided into working units. The largest group worked in the gravel pit – Kiesgrube, another one on the Bug river – Wassergruppe, another one was obtaining firewood and wood for furniture production and construction – Holzgruppe. The office – Schreibstube – was operated by German and Czech Jews. The construction and maintenance of the barracks was carried out by Baukolumne, headed by a German Jew. During the harvest, a special working unit – Bauergruppe – worked on the farm near the camp. In the summer of 1942, the Wegebau unit was created to build a road connecting the labour camp with the extermination camp. After the road was built, the significantly reduced Wegebau unit was responsible for maintaining the order of roads inside the camp. Large groups of prisoners were employed inside the camp, in craftsmen’s workshops, as well as in farm buildings: stables, pigsty, hen house, bakery, fox and rabbit farms.