Deadly Secret by TJ Logan

He steps into the shadows to pursue a killer…

F.B.I. Special Agent Beckett O’Halleran values Family, Honor, and Loyalty. A botched undercover assignment results in the brutal murder of his partner. When the killer is set free by a Deputy Director on the take, Beck walks away from the Bureau. He vows to stop at nothing to avenge his partner’s death, including using an innocent woman.
She is dragged into the shadows by her mother’s past …
A deadly secret from the past threatens Gwendolyn Tamberley’s life. Thrust into the crosshairs of a merciless psychopath who will destroy anyone who threatens his empire, she becomes the center of a firestorm between the Russian mafia, the F.B.I. and a former agent hell-bent on retribution.
Will deadly secrets destroy them?
Gwen’s only hope is the man who’s been deceiving her. And Beck must choose between his obsession with vengeance and the woman who’s come to mean everything to him.