Tomorrow marks the 25th anniversary of Sarah Spiers disappearance from Claremont.

The search for her killer was Australia’s longest and most expensive investigation.

Last month Bradley Robert Edwards was sentenced to life in prison for the murders or Jane Rimmer and Ciara Glennon,

But there wasn’t enough evidence to convict Edwards of the suspected murder of Ms Spiers, whose body has never been found.

Journalist Bret Christian has now detailed the notorious Claremont serial killings in his new book Stalking Claremont: Inside the hunt for a serial killer.

Speaking with 6PR’s Liam Bartlett this morning he said the book reveals parts of the case “we didn’t know”.

“What I set out to do was find out what went right, and what went wrong with the investigation.”

Click play to hear the full interview.