Week 4 - 5 Colin Pitchfork Case

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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

[MUSIC]

I said at the beginning that

DNA technology has brought fundamental changes to

forensic science and changed the way that convictions can be brought for criminals.

But DNA technology has also done something else.

It has also given us a very

powerful technique to prove that people are innocent.

So let's go back to the first case where DNA was used, and we

will see that the first person who was investigated using DNA profiling

was not found guilty; he was proven innocent by

DNA technology, even though he had confessed to the crime.

So let's go back to a small town called Narborough in England in 1983.

And the body of a teenager, she was just 15,

called Lynda Mann, was found in the countryside

outside the town,

and she'd been raped and murdered.

In 1983, technology only allowed forensic scientists to show that

the killer had blood type A, and that was all.

In 1986, a second victim, also 15, was found - Dawn Ashworth.

And then something odd happened.

A local guy, a young man called Richard

Buckland, confessed to the murder of Dawn Ashworth

but he insisted that he had not murdered Lynda Mann.

Well, because of the similarities in the way that the two murders had

been committed, the local police were convinced

they'd been done by the same person,

so they wanted some way to show

that Richard Buckland had been responsible for both killings.

So Narborough's not that far from Leicester

and they asked Alec Jeffreys to help.

So they supplied him with samples from both crime scenes

and a sample from the confessed killer of one Richard Buckland,

and Alec Jeffreys did the DNA analysis, and got a very surprising result.

The DNA of the suspect did not match the DNA from either crime scene.

Richard Buckland had killed neither of them.

Well, why had he confessed?

We can speculate about the reasons why he confessed,

but people do actually confess to crimes they didn't commit,

so any confession really does have to be corroborated with some other evidence.

Well, Alec Jeffreys was able to give the

police one useful piece of news - they were right

in saying that the same man had committed both murders.

Well, in an investigation a little reminiscent of the Griffiths case back

from the 1940s, which we'll talk about in another lecture, the local police

decided to do DNA screening of all men in that area.

So they're assuming that the murderer was a local man,

but they were able to narrow down the

search because they knew that the killer was

blood type A, so they only had to do DNA screening of everyone with blood type A,

and that added up to over a 1,000 men.

And in all those samples, there were no matches at all.

Then there was a break in the case.

A woman in a pub overheard a conversation,

and in that conversation, a local man called Ian Kelly was

saying that when he gave his blood sample for the DNA work,

he had done it under the name of a friend and colleague called Colin Pitchfork.

Which means that the blood sample, the DNA sample,

labelled Colin Pitchfork had actually come from Ian Kelly.

The woman told the police,

the police arrested Colin Pitchfork,

and he was obliged to give a genuine sample.

And of course, as you would expect, his DNA matched the DNA from the crime scene.

Well, with that evidence in place, Colin

Pitchfork confessed to both murders. And that's

quite interesting, because he confessed even though

this was a brand new, untested technology.

Well, he was found guilty, sentenced to life in prison, to serve a

minimum of 30 years. And at the time of recording, he's still in prison.

[BLANK_AUDIO]

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