The Distant Echo by Val McDermid

On a freezing morning in Fife four drunken students stumble upon the body of a woman in the snow. Rosie has been raped, stabbed and left for dead in an ancient Pictish cemetery. The only suspects are the four young men  now stained with her blood.
25 years later police mount a cold case review.  when two of the four die in suspicious circumstances, it seems that someone is pursuing their own brand of justice.
I love the way VMcD writes.
was a bit disappointed with the outcome of this though.