Dangerous Girls by Abigail Haas
It feels like everyone on the internet managed to get an ARC of this book, and I can't locate one anywhere! Either way, I've only heard fabulous things about it. It's girl's best friend gets murdered, girl tries to figure out what happened, people start accusing said girl. Exciting stuff. Also, it takes place on their Spring Break, so it's a nice paradise-y feel. Minus all the murder.