Week 4 - 11 Peter Falconio & Joanne Lees Case; Summary

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Del curso dictado por Nanyang Technological University, Singapore

Introduction to Forensic Science

349 calificaciones

Nanyang Technological University, Singapore

Introduction to Forensic Science

349 calificaciones

We have all seen forensic scientists in TV shows, but how do they really work? What is the science behind their work? The course aims to explain the scientific principles and techniques behind the work of forensic scientists and will be illustrated with numerous case studies from Singapore and around the world. Some questions which we will attempt to address include: How did forensics come about? What is the role of forensics in police work? Can these methods be used in non-criminal areas? Blood. What is it? How can traces of blood be found and used in evidence? Is DNA chemistry really so powerful? What happens (biologically and chemically) if someone tries to poison me? What happens if I try to poison myself? How can we tell how long someone has been dead? What if they have been dead for a really long time? Can a little piece of a carpet fluff, or a single hair, convict someone? Was Emperor Napoleon murdered by the perfidious British, or killed by his wallpaper? *For Nanyang Technological University (NTU) students, please be noted that this course will no longer be eligible for credit transfer.

De la lección

DNA in Forensics

Opinion Poll 30:00

Week 4 - 1 Introduction to DNA16:15

Week 4 - 2 Techniques used in DNA Profiling8:16

Week 4 - 3 Polymerase Chain Reaction (PCR)4:29

Week 4 - 4 Short Tandem Repeats (STR)12:05

Week 4 - 5 Colin Pitchfork Case5:37

Week 4 - 6 Cold Cases I4:22

Week 4 - 7 Cold Cases II3:20

Week 4 - 8 Early Uses of DNA Profiling6:03

Week 4 - 9 Mitochondrial DNA9:19

Week 4 - 10 DNA Profiling of Other Species2:46

Week 4 - 11 Peter Falconio & Joanne Lees Case; Summary6:48

Conoce a los instructores

Roderick Bates
Associate Professor
Division of Chemistry & Biological Chemistry | School of Physical & Mathematical Sciences

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So, we'll conclude this lecture with the case of Peter Falconio and Joanne Lees.

And they were a couple who were touring Australia back in 2001,

and they got themselves a camper van and they were driving around Australia,

and their journey took them through

the very sparsely inhabited Northern Territory.

And as they were driving along through the Northern

Territory, they were stopped by the driver of another vehicle,

and the man in the other vehicle went off, out of Joanne's sight, with Peter.

She then heard a shot.

From that moment, Peter Falconio has never been seen again.

Joanne was captured by the man and her hands were tied together with a strap,

but she was able to escape when he was distracted, and hid in a bush.

He searched for her, didn't find her, and then he drove off.

When she felt safe, she came up, came out of the bush, was

picked up by a truck driver and taken to the nearest police station.

When the police investigated, they were never able to find Peter Falconio's body.

They did find one bloodstain on the road.

Shortly afterwards, a suspect was arrested.

And he was a drug smuggler, his business was

smuggling amphetamines across Australia, and his name was Bradley Murdoch.

But the question is, could he be linked to the crime scene?

There were no witnesses except for Joanne Lees,

so it was his word against her word.

Now, on her t-shirt, there was blood. The DNA of that blood matched Bradley Murdoch,

and the Australian forensic scientists calculated these tremendous odds.

And when you look at these odds, you

realize that blood must have been Bradley Murdoch's.

But, the blood stain was on her t-shirt, it was not at the crime scene,

so it only proves that Bradley Murdoch had come into contact with Joanne

Lees, and it does not prove they came into contact at the crime scene.

It could have been at a gas station or something hundreds of miles away.

But, they were able to extract DNA from the gear stick of the camper van,

and that DNA matched Bradley Murdoch. This puts Bradley Murdoch

at the crime scene, because it proves he was in Peter and Joanne's camper van.

And then the third piece of evidence is the

strap that was used to tie Joanne Lees' hands.

There was not much DNA that could be extracted from it,

so they had to rely on low copy number DNA,

and they were able to extract from it the DNA of Joanne Lees.

It had been tied around her wrists, so obviously, it would have her DNA.

They were able to extract from it the DNA of a man called Dr. Peter Thatcher.

Well, who was he?

Well, he was one of the forensic scientists and his DNA had contaminated the sample.

And finally, they were able to extract DNA of Bradley Murdoch from the strap.

But, this is low copy number DNA, so the probabilities that they

calculated were a lot lower than for the bloodstain on the t-shirt.

When I say a lot lower, they calculated a mere 100 million to 1, but

given that the population of Australia is about 20 million, that's pretty good odds.

[BLANK_AUDIO]

So, what do we have?

We have the blood on her t-shirt.

If we did not have the DNA technology, how valuable would that evidence be?

Well, without DNA technology, you could only use blood type,

and if he had a rare blood type, you might have got 30 to 1 odds.

What about the gear stick of that camper van?

Well, without DNA technology, you wouldn't have

got any evidence off that gear stick - nothing.

What about the strap?

Again, the only thing linking this strap to Bradley Murdoch

is the DNA, so without DNA technology, there's no evidence.

This is a statement made by one of the prosecutors at the trial,

who said, "One of these things by itself might not have been enough.

But together, there was a very damning case."

So Bradley Murdoch was sentenced to 28 years, at least 28 years in

prison, whereas without DNA technology, there would have been no case at all.

So to sum up DNA, you've seen how we

can use DNA technology to prove paternity and maternity.

You've seen how DNA technology can facilitate police work, and that something

as small as just nine cells can be a trace that can be individualized.

And you've seen that combining DNA technology with the use of DNA

databases has allowed the solving of many, many cold cases involving

both the conviction of the criminals and the freeing of the innocent.

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