The book is set in the present day. Read around 2016, likely published by a New Zealand author. The cover may have been similar to the book "We Are Liars" by E. Lockhart.
Spoilers
At the end of the book, the MC is taken to a woman's house she notices a strand of hair in the woman's handbag alluding to the fact that she was her sister's killer. There also may be some plotline around searching the caves at the beach for Moas
Spoilers
At the end of the book, the MC is taken to a woman's house she notices a strand of hair in the woman's handbag alluding to the fact that she was her sister's killer. There also may be some plotline around searching the caves at the beach for Moas