Dirt Town by Hayley Scrivenor

My best friend wore her name, Esther, like a queen wearing her crown at a jaunty angle. We were twelve years old when she went missing.

On a sweltering Friday afternoon in Durton, best friends Ronnie and Esther leave school together. Esther never makes it home.

Ronnie's going to find her, she has a plan. Lewis will help. Their friend can't be gone, Ronnie won't believe it.

Detective Sergeant Sarah Michaels can believe it, she has seen what people are capable of. She knows more than anyone how, in a moment of weakness, a person can be driven to do something they never thought possible.

Lewis can believe it too. But he can't reveal what he saw that afternoon at the creek without exposing his own secret.

Five days later, Esther's buried body is discovered.