In His Safekeeping by Shawna Delacorte

Her protector...

One by one the government witnesses who’d testified against a mob associate began to die — and now Tara Ford was the last witness remaining. Suddenly with a killer shadowing her every move, she was forced to rely on the protection of U.S. Deputy Marshal Brad Harrison — a man whose take-charge attitude made her temper flare and whose strong sensuality made her heart race.

Brad never let emotion interfere with duty. But in close proximity with all-too-sexy Tara, he forgot all the rules. His instinct to keep her safe was as basic as his desire for her. And when he held her tenderly, he couldn’t help but wonder who posed the most immediate danger — the killer or Brad’s charge.