Stromberg was a nineteen-year-old student at the University of Southern California, and a member of the Young Communist League, an international organization affiliated with the Communist Party. In the state trials, the charge brought up against her was in relation to a daily ceremony that took place at the summer camp on a loaned ranch near Yucaipa, California, where she worked as a teacher. During the ceremony, Stromberg supervised and directed the youth in raising a red flag, and in pledging allegiance to "the workers' red flag, and to the cause for which it stands, one aim throughout our lives, freedom for the working class." Stromberg was also found to have owned a number of books and other printed materials advocating violence and armed uprisings, though she testified that none of such materials were employed in her teaching of the children.