CluesThe muttering at the Quidditch matchDuring Harry’s first match, Snape looks as if he is cursing the broom. The book later shows he was holding Quirrell’s jinx back.Setup1 · Harry Potter and the Philosopher's Stone · The first Quidditch matchHarry’s broom bucks. Hermione sees Snape staring at him and muttering, and she sets fire to Snape’s robes to break his concentration.The scene is staged so the obvious suspect is the teacher who already dislikes Harry.PayoffHarry Potter and the Philosopher's Stone · After the traps under the schoolQuirrell tells Harry that he himself was jinxing the broom, and that Snape’s muttering was a counter-curse. Snape’s refereeing and his glares were cover for protecting the Stone, not for helping Voldemort.People in this thread4Harry PotterStudentGryffindorStudentHermione GrangerStudentGryffindorStudentSeverus SnapePotions master, later headmasterSlytherinProfessorOrder of the PhoenixQuirinus QuirrellProfessorProfessor
