The castle was used as women's prison in the Kingdom of Yugoslavia, and it was seized as Upper Carniolan headquarters of the Nazi German Gestapo during the war.

[8] A memorial and a museum dedicated to the victims were set up in part of the building, which today houses a psychiatric hospital accepting patients from all over the Upper Carniola region.

During the war, the Germans held 11,477 hostages at Kacenštajn Castle; 849 inmates were killed,[9] and 5183 were deported to Nazi concentration camps such as Mauthausen.

[10] Mass graves of tortured and shot Slovenes are located in the castle park[11] and in the Draga Valley 1.6 kilometers (0.99 mi) to the east.

[15][16][17] The Mazevec Crevasse Mass Grave (Grobišče Mazevčev pruh) is located north of Kamen Castle, on the edge of a quarry below a large spruce tree, and is 10 m long.

It has a cupola vault, a bell tower centered with the front side of the church, and furnishings created by Leopold Layer (1752–1828) and Janez Vurnik (1849–1911).