Feathered by Laura Kasischke (2008)

A teen novel about three girlfriends who travel to Mexico for spring break, and something awful happens to one of them. Beautifully descriptive of Cancun and at the same time, wonderfully eerie and spooky and tense in the events leading up to the drama. I actually had to put the book down at one point, I was so worried about these poor girls. And the author's description of the girls walk through a debauched spring break party at Club Med is more horrifying than almost anything else in the novel.  Chilling.