Night Work — Chris Culver

Hana Blackwood is a woman without an identity. Once, she was a combat medic in the US Army. Now she's a civilian. Then she was a decorated detective with the St. Louis county police department. Now, she's not. She had a family once, but she lost them to a civil war most of the world has forgotten. She's adrift. 
Then she meets the Romero family.
 
Someone murdered their son three years ago. The police never even found a suspect. Hana doesn't know the victim or his family, but she understands loss. She can't bring the victim back, but maybe she can help a family understand their son's death.
 
Only, the victim was hardly innocent. And his killers haven't gone far.
 As Hana investigates and draws closer to the truth, dangerous men draw closer to her. But Hana's no damsel in distress. She's smart, capable, and absolutely lethal. 
 
Unfortunately, so are the men she's hunting. Night Work is the first thrilling novel in New York Times' bestselling author Chris Culver's Hana Blackwood series. If you like Lee Child or David Baldacci, you'll love this series.