Milkshakes, mermaids, and murder

the long version

"Ellie Avery planned a perfect family getaway: fun in the sun on Florida's Gulf Coast, with a side visit to the eBay vendor who'd mistakenly sent her the wrong handbag. But what should have been a simple exchange turns into a fatal transaction when Ellie discovers Angela495 floating face-down in her pool. With some savvy snooping, Ellie learns that Angela's dangerous double life included blackmail, compromising photos, and a scandalous secret that threatens a local celeb. When a kidnapping shatters her family's safety, Ellie leaves the white sands behind to face down a killer whose warm Southern charm masks a cold, cold heart" -- from publisher's web site.