No Good Deeds by Laura Lippman
Would you sacrifice your life for the life of another? That's the choice Tess Monaghan must face . . .
When the body of Federal Attorney Gregory Youssef is found dumped on the edge of Baltimore, every cop in the city is determined to catch his killer. But four months on, no one has been brought to justice and the department is under massive pressure to deliver a suspect. Meanwhile, Tess' boyfriend insists on helping a homeless black teenager. He brings Lloyd home for some food and a bed for the night, but when Tess mentions the Youssef case, Lloyd freezes.
That night, Lloyd sneaks out of the house and disappears. What is the link between Youssef's death and the teenager? Tess tracks Lloyd down and convinces him to share what he knows - which she then passes on to the press on the condition that Lloyd's name isn't used. But they use Tess' name instead.
Before long the situation spins wildly out of control, leaving Tess to fear not only for Lloyd, but also for those closest to her . . .