In 2009, a Sydney family of five were beaten to death in their home. The Lin family murders became one of Australia’s most renowned murder investigations.
But with no signs of forced entry, investigators suspected someone close to the family.
With no known suspect, forensic experts searched the home for clues. Among them was Jae Gerhard, who helped uncover ‘Stain 91’, a crucial piece of evidence.
Forensic biologist Jae Gerhard unpacks what she found on the Crime Insiders podcast:
“We’re doing little spot tests on anything that looked like it could potentially be a blood stain. And so you’re using your little filter paper and your chemical reagents. Is it changing colour? No, discard, moving on,” Gerhard said.
“There’s three of us working on our hands and knees, spot testing… and one of them was that infamous Stain 91.”
Tests revealed Stain 91 contained DNA from five individuals from the Lin family.
“It wasn’t a drip of blood… it was like what we would call a swipe mark.” This suggested a blood-stained object had touched the surface, Gerhard said.
The evidence was challenged by Defence lawyers, who questioned whether it was blood or not.
“Could it be a false positive? Well, yes, it could be.”
Stain 91 helped establish a circumstantial case against one of the family members, combined with evidence like motives and alibi.
Hear more about the case on Crime Insiders, taking you beyond true crime. In groundbreaking interviews, explore the world of policing and forensics through stories from the world’s most experienced and decorated experts.