Poltergeist

In her second book of the Greywalker series, Kat Richardson revises Harper Blaine's character to solve the mystery of a ghost-haunting that doesn't involve a real ghost. However, since Harper's client doesn't believe in ghosts, despite the fact that the group created one, Harper is charged to prove that the ghost does not exist. The plot thickens when one of the group members is murdered.

Utilizing the help of her friends Mara and Ben, as well as that of Carlos, a necromantic vampire, Harper needs to find and stop Celia's ghost from hurting others, as well as conceal her abilities from Solis, the human detective on the case of the murdered group member.

In this book Harper is more adept at sliding into the Grey and can actually slip through time (only the ghostly timeline; if there is a building in Harper's time but not in an earlier one, she can slip through time to go "through" the building instead of around).

Harper's relationship issues still haven't been resolved at this point. She chats with him briefly on the phone a couple times and then at the end he shows up. I think he offers her a companionship that she needs but doesn't want the relationship that goes with it.

I still liked this book and series, but I honestly stopped reading it for a month when I was about 85% of the way through, simply because I had a paranormal overload and needed a break. The story drags on a little and most of the action happens in the beginning and near the end. The middle of the book is just fact-finding and sleuthing that is necessary for a private investigator to solve a crime.

There is still a third book in her series called Underground, which I will get around to reading eventually. :)