This is a film of dead-ends & false leads. Unfortunately the biggest false lead & dead end is the film itself. At 151 minutes running time it feels, by it's conclusion, as if someone who had promised to take you somewhere had finally pulled up into a lay-by & said "That's it!" It's 2 & 1/2 hours of frustrated people getting more frustrated & leaving you......guess what.........? A long story which ends with "in the end it might be this or that or the other but we'll never know for sure." is just a long wind-up. The objection; "But it's based on real life events!" only means that it would make suitable material for an interesting documentary, perhaps on the frustrations of inconclusive police investigations. Documentary, or even Docu-drama material it might be, but as a movie it leaves you as cheesed off & thwarted as every single one of it's depressed & disillusioned protagonists who, understandably fall out with each other in utter weariness & despair. It's no spoiler to mention that one detective quits the case eventually, basically because it's not getting anywhere - I wish he could have warned the rest of us before the film started then we could have done the same! To make a worthwhile story or movie, it should have a Beginning, a Middle & an End whereas THIS specimen has a Beginning, an endless middle & a couple of speculative footnotes! I'm not faulting the performances, or the casting, which is (sometimes painfully) appropriate - hence the two stars. For a PRODUCER, however, it is critical to be able to distinguish twixt what makes suitable story/film material & what might be best told, detail by chafing detail, in an honest documentary. A big waste of a LOT of time.