And Hell Itself Breathes Out. SIS Case Files, #1

Evan Garrett is a psychic DC homicide cop, and his latest case is triggering all his instincts. When one murder becomes two, he can't help but start connecting the dots, putting cases and clues together. He's not the only one, though. John Benchley, director of Special Investigative Services, a tiny government agency attached to Homeland Security which deals with darker realities, and his team are soon on the case, and they bring Evan and his special skills on board.
Both bisexual, Evan and John find they are attracted to each other, even as they work together to solve this string of murders which keeps growing in scope. Their serial killer seems to be moving toward darker and darker deeds with every murder and ritual performed. Can John and Evan find solace in each other, even as murderous men and demonic forces threaten not only their own team, but the city as well?