It was meant to be the trip of a lifetime for Perth mother Avril Croft and her teenage daughter, sailing around Australia on a yacht.

Instead they were murdered – and their bodies dumped into shark and croc infested waters.

Garry Whitsed was charged with strangling his lover, shooting her daughter and disposing of the bodies to cover up his horrible crimes.

And he came up with an incredible tale of how he said they died.

Without the bodies, police and prosecutors had to prove that Whitsed’s explanation was a pack of lies.

Tim Clarke is joined by Dr Claire Ferguson - Associate Professor at the School of Justice at Queensland University of Technology – a specialist in cases where there’s been a murder, but no body is found.

And she delves into the difficulties of proving such cases – and what the history of them tells us about the perpetrators and the police who hunt them down.

For all the latest on courts and crime visit thewest.com.au. If you have a question for the team or cases you'd like explored, please get in touch. Email courtintheact@wanews.com.au