AYes. Early in the movie, it's suggested that Melanie and Dill had consensual sex when they return to the motel, and Melanie asks him, 'Dill, you'd never say anything? Tell anyone?' When Dill has to leave town for a few days, Melanie starts going out with Franklin (Rory Harrity). Again, it's only suggested in her conversation with Merritt, the night after Melanie comes home drunk, that she also had sex with Franklin. Only suggestions. Nothing overt. However, when Dill returns and corners Melanie in the room at the Leland Motel where she was supposed to be meeting Franklin, it's obvious from her behavior, her open dress, and her messed hair that Dill forced himself upon her against her wishes.