True Blue by David Baldacci

As former D.C cop Mace Perry investigates a mysterious high-profile homicide in a last-ditch attempt to get her badge back, she finds herself on a collision course with the dark side of national security in this New York Times bestseller.

Mason "Mace" Perry was a firebrand cop on the D.C. police force until she was kidnapped and framed for a crime -- and then spent two years in prison. Now she's back on the outside and focused on one mission: to be a cop once more.
Her only shot to be a true blue again is to solve a major case on her own. But even with her police chief sister on her side, she'll have to work in the shadows: A vindictive U.S. attorney will stop at nothing to send Mace back to jail. Enter Roy Kingman . . .

A young D.C. lawyer, Roy meets Mace after the murder of one of the firm's female partners. Soon Roy and Mace are investigating together -- and uncovering surprising secrets from both the private and public sectors of the nation's capital.