Extreme Honor by Piper J Drake

HONOR, LOYALTY, LOVE
David Cruz is good at two things: war and training dogs. The ex-soldier's toughest case is Atlas, a Belgian Malinois whose handler died in combat. Nobody at Hope's Crossing kennel can break through the animal's grief. That is, until dog whisperer Evelyn Jones walks into the facility . . . and into Atlas's heart. David hates to admit that the curvy blonde's mesmerizing effect isn't limited to canines. But when Lyn's work with Atlas puts her in danger, David will do anything to protect her.
Lyn realizes that David's own battle scars make him uniquely qualified for his job as a trainer. Tough as nails yet gentle when it counts, he's gotten closer to Atlas than anyone else-and he's willing to put his hard-wired suspicion aside to let her do the same. But someone desperate enough to kill doesn't want Lyn working with Atlas. Now only teamwork, trust, and courage can save two troubled hearts and the dog who loves them both . . .