The Execution Site served as a cemetery where victims of the Treblinka I Labour Camp were buried — Jews, Roma, Sinti, and Poles who died as a result of starvation, exhaustion, and disease, or who were murdered. It was also a site of executions by shooting, where camp prisoners and people brought by the Gestapo from prisons in Sokołów Podlaski and Warsaw were killed.
The estimated number of 10,000 victims of the Treblinka I Labour Camp does not correspond to the number of individuals buried at this site. Some prisoners were buried at the place of execution, while certain groups deemed unfit for work were killed in the gas chambers of the Treblinka II Extermination Camp.
In 1944 and 1946, the Main Commission for the Investigation of German Crimes in Poland conducted partial exhumations and examinations of selected graves. The investigations showed that the cause of death of many victims included gunshot wounds to the head as well as injuries inflicted with blunt instruments. The exact number of those buried at the Execution Site remains unknown.