The first ten books can be seen here. The second ten are here. Nos. 21–50 are below this post.
51. John Hart, The Last Child (2009) (10/10/16)
An especially interesting part of the book, and of the plot, concerns a "hush arbor," a secret place where African and Indian slaves would go to practice their Christian religion. "Nobody here wanted them learning about Jesus and God and stuff," explains Johnny to his best friend. "They didn't want a bunch of slaves thinking they were equal in the eyes of God. Do you see? If you're equal, then nobody should own you. That was dangerous thinking if you owned slaves. . . . They were too smart to build a church because they knew somebody would find it. But woods are just woods, a swamp is just mud and water and snakes and shit. So that's where they'd go. They'd sing their songs to God, dance on the dirt, and testify to their new faith." It was also where, when they were found out, the miscreants were hung as punishment and the freedmen's cemetery sprung up.
A perfectly satisfying mystery, with good emotional complexity. Although one of the bad guys caught my attention early on, the actual resolution was a good solid surprise.