Mystic River
Nobody likes to see someone go down for a crime they never committed, but that's exactly what happened when Dave Boyle (Tim Robbins) took the blame for the murder of Katie Markum (Emmy Rossum). Dave, who confessed to murdering a pedophile, was threatened and coerced by Jimmy Markum (Sean Penn) into admitting that he killed Katie. Jimmy violently murdered Dave as retribution and dumped his body in the Mystic River—only a few hours before Katie's actual killers were identified.