At least 30,000 inmates died in Sachsenhausen from causes such as exhaustion, disease, malnutrition and pneumonia, as a result of the poor living conditions. Many were executed or died as the result of brutal medical experimentation. Over the course of its operation, over 100 Dutch resistance fighters were executed at Sachsenhausen. Dutch Freemasons were also sent to the camp including the Grand Master of the Grand Orient of the Netherlands, Hermannus Van Torgeren, who died there in March 1940, after being arrested by Klaus Barbie. The Dutch subsequently sought the extradition from Czechoslovakia of Antonín Zápotocký, who became President of Czechoslovakia, for his alleged role in the murder of Dutch prisoners during his time as a "kapo" at the camp. According to an article published on 13 December 2001 in "The New York Times", "In the early years of the war the SS practiced methods of mass killing there that were later used in the Nazi death camps. Of the roughly 30,000 wartime victims at Sachsenhausen, most were Russian prisoners of war".