The Angry P.I. — Bob Moats

It was a quiet morning in the Cold Case Department office, as Detective Russ Baker sat relaxing. Then his ghost partner, Wes, materialized and said they had a new case of a murdered P.I. who was killed by an unknown woman. Russ and Mary investigates numerous suspects from the P.I.'s list of women he caught cheating on their husbands and hated him enough to murder him. Would they find the right woman so they could send off the P.I. who was disrupting the ghost Squad file room. This is the 11th Ghost Squad book and it's a novella, shorter than a novel but longer than a short story.