David Bain spent 13 years in prison after being found guilty of killing his family in 1994 - however he always maintained his innocence and he was acquitted in a retrial in 2009.

On the 24th of June, 1994, Robin (58) and Margaret Bain (50) and three of their children, Arawa (19), Laniet (18) and Stephen (14), were found dead in their Dunedin home.

Four days later, the only surviving family member - 22 year-old David Bain - was arrested for their murders.

Martin van Beynan's written extensively on the Bain family murders, including his own podcast Black Hands.

David Bain was found guilty of murder in 1995 and sentenced to 16 years in prison.

But in 2009, he was acquitted at a retrial.

Stuff senior reporter Martin van Baynen sat through the three month retrial and does not believe the evidence pointing to Robin Bain being the murder stacks up.

Go to this episode on rnz.co.nz for more details