Jar City by Arnaldur Indridason

From Gold Dagger Award—winning author Arnaldur Indridason comes a Reykjavík thriller introducing Inspector Erlendur
When a lonely old man is found dead in his Reykjavík flat, the only clues are a cryptic note left by the killer and a photograph of a young girl's grave. Inspector Erlendur discovers that many years ago the victim was accused, but not convicted, of an unsolved crime, a rape. Did the old man's past come back to haunt him? As Erlendur reopens this very cold case, he follows a trail of unusual forensic evidence, uncovering secrets that are much larger than the murder of one old man.
An international sensation, the Inspector Erlendur series has sold more than two million copies worldwide.