Chennai: A 19-year-old youth was arrested under the Pocso Act for threatening a schoolgirl near Tiruttani, demanding that she persuade her elder sister to accept his love proposal.Gopal, 19, intercepted the Class X student when was walking home from the bus stand after school, said police. He threatened her and demanded that she convince her elder sister, a Class XI student, to accept his proposal.The younger girl subsequently informed her parents about the incident. Following a complaint by her mother, Tiruttani All Women Police registered a case under the Pocso Act and arrested Gopal.