The Medusa Files, Case 9: Shattered Stone

Another bomb has exploded and more Kin are infected, including Lachlin's sister. If they don't stop the bomber, more Kin will become human and go insane, or die. Every instinct Morgan has screams the madman toying with her, Ander, is behind the attacks, but she can't prove it. All she knows is that he wants her dead and he wants control of the Kin High Council. Except Gage doesn't believe her and proving herself right could get her infected-or worse, killed.