Academy of Deadly Arts by Helen Scott

The afterlife isn’t all it’s cracked up to be.

Purgatory isn’t exactly where Avery thought she’d end up when she died. What’s worse – she’s forced to attend an academy to understand what it means to be a spirit. If she can figure out why she’s stuck in limbo, there’s hope for her to find her final resting place.
That all changes when Avery stumbles upon the graveyard of a serial killer, one who has no intention of stopping. How something dead can die again, Avery doesn’t know, and she has no intention of finding out, that is until she gets attacked by a demon. When sinfully sexy spirits come to her rescue it seems too good to be true. She should have known there was a catch. Now, she has access to strange powers that no other ghosts have even heard of.
With demons hunting her, a murderer tracking her down thanks to her new powers, and sexual tension between her and her saviors, Avery must learn how to control this new magic and solve the murders before the killer strikes again. She’s the next target – and this time, there’s no coming back from the dead.