6th Sense by Kate Calloway

The last person private investigator Cassidy James expects -or wants- to hear from is her ex-lover, psychologist Maggie Carradine. But when a distraught Maggie calls begging for help, Cassidy puts her anger and hurt aside and agrees to meet Maggie face-to-face. Her misgivings are reinforced when Maggie reveals the bizarre manner in which she has just witnesses not one, but two separate, brutal murders. The victims are both connected to clients of Maggie's and the gruesome clues intensify Cassidy's fear that the killing has just begun.