I'm reading Occupied City by David Peace (Red Riding Quartet, The Damned United ) at the moment - it's the second part of his Tokyo Trilogy.
Occupied City pieces together the investigation into the 1948 Teikoku Bank massacre, in which a man posing as a doctor from the occupying forces pretended to administer a dysentery vaccine to 16 bank employees, and instead poisoned them with cyanide, killing 12 instantly. Hirasawa Sadamichi was convicted of the killings but many in Japan believe he was innocent.
All the reports on Amazon say it's an experimental text and a difficult read but I'm zipping through it and enjoying it loads. I think the Amazon reviewers have clearly only ever read The Damned United and think that's his usual style - which it is, and isn't.