Kindred Killers by Gary Starta

Homicide Detective Stanford Carter uses Zen meditation to deal with the gruesome crimes of humanity. But his composure is severely tested when an unfaithful husband and stripper are not only murdered but showcased for their immoral lives. To test his mettle further, department policy is jeopardizing his romance with his CSI colleague Jill Seacrest. Marrying colleagues is prohibited and Carter must either end his romance or have Jill put in for transfer. The private detective hired by the family of the victims becomes the only suspect. Carter theorizes someone with knowledge in law enforcement is responsible for leaving clean but disturbing crime scenes. Further investigation leads him to believe a pair of killers might be working as serials. As Jill goes undercover to investigate the PI’s social life, Carter fears he might not only fail to stop the vigilante killings but lose the love of his life.