Succession - The Garza Series, #2

Paul Garza wants to integrate into peaceful society after traumatic experiences in undercover law enforcement and before that, combat. But the son of a man he arrested is assembling a small army of killers to come for revenge, and a mystery surrounding the family of Garza's lover distracts him from the danger at hand. As the killers close in, the mystery unfolds to reveal a succession plan so poorly crafted that instead of producing continuity, it produces destruction.