Then there was Ian Rankin's Blood Hunt. Although I have read two of Rankin's books, neither has been an Inspector Rebus title for which the author is well known.
Here's another conspiracy tale. Jim Reeve, a journalist, is onto a 'big' story in the states when he apparently commits suicide. His brother Gordon Reeve, an ex-SAS operative, doesn't believe it and takes the revenge of this death as a challenge. (This would make a great Bruce Willis movie.)
Again the violence committed, even by our hero, was over-the-top.
Here was another book that kept me up past my bedtime.