Death Retroactive - The Retro Justice Force Mysteries, #1

Save the girl, or save the Timeline Standing over the dead body of a 17-year-old girl, Detective St. John Deveraux hopes she was murdered. It's the only way he can save her. He's part of a new police force in an alternative Seattle that can execute a murderer before the crime is committed, but only if it meets the agency's strict guidelines. So far none have.  As Deveraux closes in on the girl's killer, he finds his own agency implicated in her death and faces an impossible choice. If he convicts her killer, he'll reset the Timeline and lose all his knowledge of the corruption in his own force.
But if he holds his superiors to account, he'll lose the chance to impose the sentence of Death Retroactive and do the one thing he came here to do... raise the dead.