Spectre by Phaedra Weldon

The second novel in the Zoe Martinique Investigations series seems just slightly less dark than the first one. Zoe has mostly recovered from her adventures in becoming a Wraith, aside from having lost her voice completely, though she's picked up enough sign language to compensate for it, mostly. She's become romantically involved with Detective Daniel Frasier, but between the injuries he sustained in the last battle and his innately chivalrous nature, they haven't consummated their attraction yet.

Her mysterious client, Maharba, contacts Zoe with a "make-up" assignment, sending her to a political fundraiser for Congressman March Knowles, asking her to listen in on any meetings he might have with a certain businessman (very similar to her first troublesome assignment for Maharba). Fortuitously, Daniel is also attending the fundraiser, to keep an eye on things for the Atlanta PD, so she gets all prettied up and it looks for a bit as if she might have a lovely night on the town with her beau.

Unfortunately, when she goes out of body to listen in on the meeting, a woman is murdered in the restroom where she's left her body resting, and things begin to be complicated.

There are a couple of magic-using factions that are vying for power, and they've begun a cycle of violence aimed at possessing for their sides five objects of power called Eidolons, which have been secretly held by five different astral travelers for decades. Zoe and Daniel, and an undercover detective named Joe, who was coincidentally the same person who helped Zoe revive after she ended up on a slab in the morgue in Wraith, must try to unravel the plots and counterplots.

Zoe gains a few new mystical abilities, finds out more than she bargained for about her family and friends, and remains sexually frustrated to the bitter end. Still a fun series.