A let down

Just got back from reviewing this for the Dublin film festival.
In brief; not a bad idea for a film, I know its based on a real case of murder. It is a powerful film but just so relentlessly bleak and, really, after a while I began to lose interest. Not a good sign.
The acting it has to be said is superb but the scene by scene flash back gets very repetitive and in the end, nothing whatsoever is revealed or properly explained.
I couldn't wait to get out of the cinema. 2/4 stars.