Ashley Harper is the daughter of Melanie Harper, an accomplished woman who grew out of her trauma from being raped as a teenager. To the horror of both of them, the accused man not responsible for raping Melanie, Sean Roberts, was exonerated when the rape kit from the case was finally run, revealing Roberts wasn't guilty and getting him released from prison.
Roberts later met Ashley and tried to make a pass at her. By Roberts' account, when Ashley laughed, Roberts had a breakdown that "just happened" and violently raped and murdered Ashley. Along with rejection, the motive was partly Roberts' rape trauma from being raped and tortured in prison.
Roberts was convicted and imprisoned again, with Melanie being left to grieve and Joe Biden speaking out about the rape kit crisis that prevented Roberts' exoneration for years. (SVU: "Making a Rapist")