Testimony of Dr. T. Cytron, born in Bialystok, Poland, 1908, regarding the investigation of the explosion of a building on Czysta Street in Bialystok, June 1943 Explosion of a building on Czysta Street in Bialystok, June 1943; deaths of two people in the explosion; transfer of the wounded to a hospital in the ghetto; Cytron's period of service as the duty physician in the hospital; investigation of the explosion by order of Hauptsturmfuehrer Fritz Friedel and Untersturmfuehrer Klein in the presence of Barash, the Judenrat chairman, and Markus, the head of the Jewish police; manufacture of the grenades that caused the explosion in a ghetto workshop was ordered by the Jewish underground in the ghetto.