Uprising by Ellen Fritz, Book II in The Second Birth Chronicles
Detective Ted Peterson’s investigation of a suspicious death case leads him to suspect Lexi Collins and her boyfriend Adam. What he discovers is that they’re extraterrestrials. Now he's without backup and caught up in the conflict between two alien races secretly inhabiting the earth. One race, the Dabih, is abducting women and running experiments. The other, the Mira, seem friendly toward humans – especially their attractive leader Sindri - but can Ted trust aliens to help him find the Dabih and rescue the kidnapped women before it’s too late?