The Last Echo by Kimberly Derting - USED

Violet has always kept her strange ability to sense dead bodies a secret from everyone except her family and best-friend-turned-boyfriend Jay. But now she's using her gift to help track down murderers, working in a group that includes the mysterious and dangerously attractive Rafe. When Violet discovers the body of a college girl murdered by "the girlfriend collector", she is determine to solve the case. But now the serial killer is on the lookout for a new "relationship" and Violet seems to have caught his eye...