The Sheltering Tree — Rick Nichols

How well do we really know anyone? When John Logan's best friend, Mason Killian is critically wounded in a drive-by shooting, Logan vows to find those responsible. But Logan's investigation soon reveals that his friend has secrets...a lot of them...the kind of secrets that can destroy a friendship...and get people killed. As Logan descends deeper into the web of deceit, intrigue, and violence that is Mason Killian's life, he will discover the demons that have haunted his friend for decades, and come face-to-face with the enemy who wants Killian dead.