High Road 101 (Secret's Out) - High Road, #1

Nick Coyne is Santa Fe PD's rock star crime scene investigator. When it comes to murder, he can solve them out of hand, finding the most well-hidden evidence, the most obscure suspect, and making hardened suspects confess to their crime. However, that is because murderers can't hide from the dead, and the dead won't leave Nick alone until he's caught their killer. For eleven years Nick has been able to cover up his secret, but a recent policy change pairs him with his best friend and a grouchy detective.
He struggles to keep his secret hidden from them, but when he discovers one of his victims was killed a serial killer, who is one of his co-workers, he stops caring about hiding. He realizes that in order to catch this murderer, he will have to put himself right in the serial killer's path. Nick must now race to expose the killer before he becomes one of the spirits he's spent his life helping?