Mystic River (2003)

When the daughter of ex-con Jimmy Marcus is murdered, two of his childhood friends from the neighborhood are involved. Dave, a blue-collar worker, was the last person to see her alive, while Sean, a homicide detective, is heading up the case. As Sean proceeds with his investigation, Jimmy conducts one of his own through neighborhood contacts. Eventually, Jimmy suspects Dave is the culprit and considers taking the law into his own hands.