Disappear (Beckett #1)
Mary Martinez

Keira Cavanaugh is the only witness to a hit ordered by a crime boss. The safe house is compromised and the same hit man shoots Tyler. Fearing Tyler is dead, Keira plans revenge on the crime organization. She must fake her own suicide in order to survive.
When Tyler discovers what Keira plans, he realizes he must stop her before he loses her for good.