This movie is really good! I do have some reservations about how things wrap up; it’s certainly not bad, but I don’t think it completely satisfies me. However, everything else in 'Mystic River' is top-notch. The actors are fantastic, including the lead performers Sean Penn, Tim Robbins and Kevin Bacon, as well as Laurence Fishburne and Marcia Gay Harden in supporting roles. Bacon and Fishburne together create a really enjoyable partnership, much better than what Clint Eastwood produced with Charlie Sheen in his 1990 film 'The Rookie'. The final moments do seem to fit the story that’s been told, especially concerning Robbins' character, but I wasn't entirely persuaded by the identity of the person who turns out to be responsible. That being said, it isn’t a poor ending; as mentioned earlier, it remains engaging regardless.

Source on TMDB