Gossamer Ghost (Paperback) by Laura Childs

Carmela Bertrand knows that Halloween in New Orleans means a week of rabble-rousing, costumed craziness--and she can't wait to get the party started. But when a local antiques dealer turns up dead, Carmela suddenly finds herself in a real-life danse macabre...
An evening's work deciding on the class schedule for her scrapbooking shop has put Carmela in the mood to kick up her heels. But after some strange noises draw her into Oddities, the neighboring antiques shop, Carmela's night is abruptly put on hold when a bloody body falls out of a curio cabinet--and into her arms.
While shop owner Marcus Joubert was known for being an eccentric with a penchant for eclectic merchandise, Carmela never thought he was the kind of man who could inspire the passion required to kill. But when Marcus's assistant--and fiancee--Mavis reveals that a priceless death mask was also stolen, it becomes clear that murder wasn't the culprit's sole intention.
Carmela can't resist the urge to investigate the growing mystery, but as the list of suspects increases, she realizes it'll take every trick in the book to unmask the killer thief before there's another night of murderous mischief...