Task: Question Answering
Input (English): Passage: In 1933, Freya Roth is a young German girl engaged to a Nazi party member. When she realizes the true nature of his political views she breaks the engagement and turns her attention to anti-Nazi Martin Breitner. Her father, Professor Roth, does not abide by the attitude of the new order towards scientific fact.
Though his stepsons Erich and Otto eagerly embrace the regime, Professor Roth's reluctance to conform leads at first to a boycott of his classes and eventually to his arrest and a sentence of forced physical labor. His wife is permitted a five-minute visit in which the professor urges her to take Freya and her younger brother and leave the country. He dies soon after.
Freya is kept from leaving by Nazi officials suspicious of her father's work. She reunites with Martin and together they attempt to escape through a mountain pass. A squad reluctantly led by her former fiancee gives chase and Freya is fatally wounded, dying in Martin's arms just after they cross the border. Later, Erich and Otto are informed of their sister's death. Erich responds with anger towards Martin.  Otto, however, experiences an epiphany, and flees their once-happy home, rejecting the Nazis and their cruel doctrine. 
Question: What is the name of the person whose work the Nazis are suspicious of?
Output (English): Professor Roth.