Poltergeist  by Kat Richardson.  Following up her PI paranormal Greywalker, Richardson's second novel is more a classic murder mystery with supernatural elements than most genreic entries. When Private Investigator Harper Blaine is called in to investigate the possible faking of results for a parapsychology experiment, she finds herself in the middle of a murder investigation that seems to be centered around a group-created ghost. "Ceilia" is less than friendly, and before long it emerges that one particular psychopath is pulling the strings. Richardson manages to craft a solid mystery without relying over-much on supernatural or magical crutches – while the creation of the 'ghost' and the method of it's capture pull the novel into the fantastic, the investigational method is pure Ellery Queen. It's a refreshing mix, and one I wouldn't mind seeing more often.