Ms. Kait Ballenger is back at it with book three in her Execution Underground Series.

Find the Author: Website, Twitter, Facebook, GoodreadsHunters of the supernatural, THE EXECUTION UNDERGROUND are an elite group tasked with protecting humanity…but can dark temptation destroy good intentions?
Occult specialist and witch hunter Dr. Shane Grey is called upon to investigate a string of crimes that bear all the hallmarks of black magic. But he can't take on this daunting assignment for the Execution Underground alone. He'll need the help of Vera Sanders, a witch with a dark past—and a woman who disturbs him as much as she intrigues him.
Vera is determined to ignore the dangerous chemistry between herself and Shane so she can prove her loyalty to his cause; otherwise she risks the wrath of the Execution Underground once again. If she can't make Shane trust her, they won't stand a chance in hell of defeating the evil that's terrorizing their city. No easy task, considering old habits die hard…and Vera may be the very person responsible for luring Shane into a killer's trap.
Obviously this being the third means that there are two great books before it. Book 0.5 Shadow Hunter, Book One Twilight Hunter, and Book 2 Immortal Hunter.
I have not read the fourth book, but I did read Shadow Hunters and it was a really good set up to the series. The cover model does not disappoint either, I mean look at him.
You can pick up Midnight Hunter along with the rest of the series at the following links.