“It’s pretty horrible”: How forensics solves crime

A crime has been committed, and police and emergency services need to secure the scene. While gathering evidence, depending on the crime, they might need to summon forensic experts to come and use their scientific expertise to make sense of it all.

Surely, it’s as simple as taking a DNA sample? But what happens when it’s in a public space and the genetic material of many people is all over the scene?

When it comes to identifying a victim, sometimes a body is no longer identifiable. What about trying to make sense of blood spatter? What of the unreliable forensics that have put innocent people in prison?

It can be difficult to process – both the technicalities of obtaining and assessing forensic material, as well as the often confronting human side of a crime scene.

“I went to some pretty horrendous murder scenes,” says Professor Adrian Linacre, chair in forensic DNA technology at Flinders University. He’s previously worked as a forensic practitioner specialising in body fluids, blood pattern analysis and DNA typing.

He shared his experience analysing blood spatter with Cosmos’ four-part podcast series Demystifying Forensics. When it comes to interpreting these patterns, physics is everything.

“If you provide action – hitting, kicking, striking – into that blood, there is energy applied […] to make smaller droplets.

“There’s a remarkable physical relationship between the size of the blood spot and the force applied: the greater the force, the smaller the bloodspots.”

If you’ve ever wondered how forensic experts do their job, check out our four-part series below.