River's Edge by Cath Phillips
When Valentine's gay friend Ryan disappears, she is reluctantly drawn from her island to the wider world where her rules don't apply. And for Detective Jane Stewart, uncovering a motive for Ryan's murder soon becomes more than a routine investigation. But the river doesn't give up its secrets easily. River's Edge is an extraordinarily evocative novel about murder and corruption, retribution and redemption - both mystery and morality tale, it's also an exploration of human commitment.