Tempus Fugitive by Cyrus Keith

New from Award-winning author Cyrus Keith:
The Marines are done with Simon Crocker. In fact, they couldn't get rid of him fast enough after a political scandal ruined his career. Scarred and haunted by his past, looking to hide his shame under the nearest large rock, he encounters Doc Friezen, an eager young scientist who gives Simon a new mission: Scour History of its worst filth. Serial murderers, child killers, and rapists could be stopped if the right man could find them at the right time. Doc can arrange the right time with his newly-invented time machine. All he needs is the right man.
With nowhere else to go, and a chance to redeem his name, Simon accepts the doctor's offer. But after a few initial successes, he comes up against a seemingly unstoppable chameleon of a murderer, one who knows entirely too much about Simon, and about Doctor Friezen's machine. And once the killer's sights are set on the former Marine, Simon is no...