Blackwater Sound is the seventh in the Thorn series by James W Hall. Per SYKM, it won the 2003 Shamus Award for Best Novel. And it’s free right now at Kindle US and UK.
Books in this series go free or on sale from time-to-time. Not often, and you need patience, but I now have about half of them. And if you find you don’t want to wait, they’re not badly priced at $3.99 in the US, and around £3.00 in the UK.
Find Blackwater Sound for free (for now) at Kindle US | Kindle UK