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- How did Newt know? 3 answers
Near the end of Fantastic Beasts and Where to Find Them, Newt casts
revelio, showing that the Graves we see is really Gellert Grindelwald. As far as I am aware, the movie until this point had not provided any "tells" that Grindelwald had been impersonating Graves.
Thus, why did Newt cast this spell?