Splinter III: The Massacre & The Mask. Splinter: The Jodi Daniels Series, #3

Jodi Daniels survived. Now, with his feral German Shepherd Err at his side, he stalks the fog-drowned streets of Port Royal, methodically crossing names from his mental ledger of the damned. But a silent Observer watches from the shadows-documenting, understanding, and perhaps manipulating the carnage. As police and military close in, Jodi discovers that the greatest threat is not capture or death, but the revelation that someone else has been writing in his ledger all along.