Why had Luke Marks driven specially out to Windee?

Had he been murdered or had he, as the local police believed, wandered away from his car and been overwhelmed in a dust-storm?

When Bony noticed something odd in the background of a police photograph, he begins to piece together the secrets of the sands of Windee.

Here is the original background to the infamous Snowy Rowles murder trial.

Napoleon Bonaparte my best detective. - Daily Mail