The Whistler Series Series by T.J. Garrett

Forced to come to terms with his wife's death, Daniel discovers he has an affinity with other-worldly creatures. With the help of a mysterious clairvoyant, Daniel attempts to use his new-found abilities to find his wife's killer. However, all is not as it seems, and instead of finding answers, every twist and turn will lead Daniel to yet more questions. Frustrated, Daniel asks his new friend for help. Can he hold onto his sanity long enough to find the killer?