"You won't believe what happened next": a true crime special
How do you solve linked murders without witnesses? The answer, DNA.
In this episode of Discovery Matters, we have been inspired by the true crime genre. We discuss a 32-year-old cold case which was the first to be solved with DNA profiling, and a murder in Las Vegas that was solved with the smallest amount of DNA ever!
Join Dodi and Conor, and guest Kathryn Lamerton a former forensic scientist currently a Senior R&D Scientist at Cytiva, with a re-enactment helped by some of our colleagues at Cytiva for this exciting episode of Discovery Matters.
CONOR: So, Dodi, its traditional holiday season in the summer here in the north, and it's time to leave the standard way of doing Discovery Matters.
DODI: That's right. This is an homage episode, and homage to the true crime genre.
CONOR: Oh, you're so French.
DODI: I am so French. But this doesn't take place in France, but we'll get to that. This story was inspired by the recent news of a 32-year-old cold case, which was solved with the smallest amount of DNA ever.
CONOR: Yes, the case of a 14-year-old girl from Las Vegas. That's quite some story. We'll get to that. But that's not really where we want to start.
DODI: We want to go back to the very beginning. How did we discover that DNA could help us solve crimes?
CONOR: And for that, we need to go back to the 1980s, big hair, shoulder pads. Welcome to Discovery Matters - our true crime episode. It's a November night in 1983, and Linda Mann is walking home from babysitting. Leicestershire, in England, is pretty cold this time of year, and the leaves have already fallen from the trees.
DODI: Okay, I can hear the crunch of the leaves under Linda's feet.
CONOR: Those breathy dark nights. Linda's mother and father are waiting for her at home. But when she doesn't show up, they begin to worry. The next morning, she's found dead, attacked, strangled on a deserted path that she used as a shortcut, and that was known as the Black Pad.
DODI: Oh, that's horrible. Of course, somebody would die on a path that is named the Black Pad. So, who killed Linda? What happened?
CONOR: Well, that is the thing with true crime, nobody knew.
DODI: We don't know!
CONOR: Linda's murder turned into a cold case. There's a lot of twists and turns here. In July 1986, another girl, Dawn Ashworth also disappeared. Two days later, her body was found near a footpath known as the Ten Pound Lane.
DODI: Okay, so all these nicknames for the paths?
CONOR: I know it's so very English, isn't it?
DODI: Yeah, absolutely. I think we're going to learn about the notorious Black Ten Pad Pound killer.
CONOR: No, easy. These two killings had nothing to do with each other. But looking closer, you could find a connection. So, Dawn Ashworth was attacked, beaten and strangled less than a mile from the Black Pad where Linda was found dead. The case similarity and location meant that the police could link the crimes. And after three years of Linda's family waiting for an explanation, the investigation was reopened.
DODI: Okay, so we've now come to 1986, and what was special about that year?
CONOR: Mexico World Cup? No. So 1986 was when DNA profiling really began, and the case I'm going to tell you about has something to do with that. Because without DNA profiling and fingerprinting, the murder of these two girls would never have been found.
DODI: Okay, let's stop here for a minute and dive into the science. Can you tell us how DNA profiling became a thing?
KATHRYN LAMERTON: So, DNA profiling is a state-of-the-art procedure that can be used to identify individuals on the basis of their unique genetic makeup. As all cells except mature red blood cells contain DNA, any sweat, semen body fluids or skin cells left behind at a crime scene can be examined for the unique DNA profile to link a person or suspect to the sample collected from the crime scene.
CONOR: So that's Kathryn Lamerton, our colleague at Cytiva. She used to be a forensic scientist before coming to work for us. She traded CSI Wales, for Cytiva...
DODI: For Cytiva...
CONOR: Yeah, so back to Linda and Dawn. The investigation into Linda's murder reopened in 1986 after police linked the two murders. There were bodily fluids left at both scenes. So as Kathryn told us that gave them DNA clues, and investigators had some certainty that these gruesome crimes were committed by the same person. Eventually, the investigators arrested Richard Buckland, a 17-year-old who knew where Dawn's body was. When they questioned him, he would repeatedly admit to the crime, but then he withdrew that admission. Police charged him with Dawn's murder, and he was in court just a few days later.
DODI: Okay, that sounds a little sketchy. So, what could investigators do to be sure that Buckland was the guy?
CONOR: Okay, so let's go back to Kathryn again.
KATHRYN LAMERTON: So, the human genome consists of nearly 3 billion DNA base pairs. All of these are composed of the same four nitrogen base molecules. So, you have either adenine, thymine, cytosine and guanine, or ATCG for short, is simply the pattern in which these smaller molecules are arranged. So, the DNA sequence that varies between each individual and ultimately determines each person's unique characteristics. So, this means that your genome, so all of your DNA, is unique, unless you have an identical twin.
DODI: Whoa, whoa, whoa, whoa, I have twins. So, my sons, you're telling me could trick investigators if they ever did anything less than perfect?
CONOR: I'm sure they've never done anything less than perfect. So, it's a non-starter?
DODI: Well, okay, if you insist. But wait a minute, I feel like we're getting off track. Take us back to Kathryn and how we can be sure that DNA testing is accurate.
KATHRYN LAMERTON: Its why people may share the same eye and hair color, and even have similar facial features, they will not have the same DNA. So, DNA profiling is a state-of-the-art procedure that can be used to identify individuals on the basis of their unique genetic makeup.
CONOR: So, investigators tested the DNA found at the crime scene to match it with Richards DNA. But it didn't match.
CONOR: And gawp.
DODI: Dun dun dunnnn. So, then what happened with Richard Buckland? The guy that had confessed.
CONOR: Okay, we will get to that. But first, I want to take you back to 1984.
DODI: So much happened in the 80s. It wasn't just big hair and shoulder pads. There's a lot of good science happening.
CONOR: Very good science, and something important was happening in a scientific lab in Leicester close to where these crimes actually were committed. Alec Jeffreys, an eminent biochemist, was about to have one of those eureka moments, he was doing one of his experiments and pulled an X-ray film out of a developing tank in his lab. And in the image, he could see patterns in the genetic material, which completely discriminated between the three people who had been involved in the experiment. So, his lab technician, and a mother and a father. From this discovery, that variations in the genetic code can identify individuals very clearly, Jeffreys has developed genetic fingerprinting and DNA profiling.
DODI: Amazing and timely for our story. So, two years later, Buckland was being pursued by the authorities, based on his confession alone, and I can see where this is going now.
CONOR: And yes, like all good, true crime. These two stories collide. In 1986, Jeffrey's gets a call from the police, and is asked to test Richard's DNA against that found at the crime scene.
JEFFREYS (VOICE ACTOR): Hello?
CONOR: He worked through the night and found that the DNA samples didn't match.
CONOR: Yeah, I know. I mean, this was New Tech, and the police were really hesitant. Buckland had of course, confessed...
DODI: But then withdrew his confession...
CONOR: Withdrew it, confessed, withdrew. But Jeffreys knew that the science didn't lie. So, he tested it once, he tested it twice and tested it a third time, every time getting the same result.
POLICE (VOICE ACTOR): Well, one minute, we got the guy and the next we've got jack shit.
DODI: Thank you to our volunteer actor for that reenactment. But Conor, how did investigators find out who did it?
CONOR: So backed by science, the police could see that Richard didn't do the crime, and now they were back to square one. The solution they arrived at, and you're not going to believe this, was to test all the men in the area to see whose DNA matched they were mixed signals but because of the violence of the crimes committed, and the fear in the community, almost all men came to give a blood sample. After eight months they had 5,511 blood samples being tested, but still not a one that matched the DNA at the crime scene.
DODI: What a mind twister.
CONOR: I know right? You can't believe what happens next. A year after Dawn's murder in August 1987, a baker and his three friends are sitting having a pint in a local pub.
DODI: This is going to be a joke, isn't it?
CONOR: Sounds like it, but no.
KELLY'S FRIEND (VOICE ACTOR): How about that guy Pitchfork? What's he like? He works with a bakery with you, right?
CONOR: One of the friends said...
KELLY (VOICE ACTOR): Oh, yeah, we work together. I don't know he's a little funky.
KELLY'S FRIEND (VOICE ACTOR): What do you mean?
KELLY (VOICE ACTOR): Okay. Do you remember when we did the blood testing for the girls that got murdered? Like six weeks ago?
KELLY'S FRIEND (VOICE ACTOR): Yeah. Why?
KELLY (VOICE ACTOR): He asked me if I could take the test for him. He said it was because he had a conviction for indecent exposure in his younger years. He inserted my picture in his passport, drove me to the test center, and I took the test for him. He waited outside and everything.
DODI: What? You know what, I should not be surprised at all at this story because it is always at a pub. But you're telling me this guy helped Pitchfork not get tested?
CONOR: Yes, he did. The guy's name was Kelly. He covered for his friend Colin Pitchfork. One of Kelly's friends that heard the story at the pub took the story to the police about six weeks later, and Kelly and Pitchfork were both arrested.
DODI: So more than a year later, they caught their guy.
CONOR: Yeah. And the police interrogated Colin Pitchfork. They read him his rights, and they asked...
POLICE (VOICE ACTOR) : Why Dawn Ashworth?
PITCHFORK (VOICE ACTOR) : Opportunity. She was there, and I was there.
CONOR: So, Pitchfork gives the police a detailed confession of both murders, his DNA is taken, and of course, it matches both the crime scenes.
DODI: Whoa. So, what we have now is Alec Jeffreys' research, stumbling upon similarities in DNA, without those things all colliding, this killer never would have been caught.
CONOR: Exactly. And this was the first ever murder, or pair of murders even, sold with DNA. Here's Kathryn again explaining how it really works today, in forensic databases in CSI Wales well around the world really.
KATHRYN LAMERTON: DNA contains regions in which short sequences of bases are repeated multiple times. These repeats are found in many locations throughout the genome. Because the exact number of repeats at each location varies from person to person. Forensic scientists can use the information on the number of repeat units, called short tandem repeats, or STR's to create a DNA profile and identify individuals. So, a DNA profile basically consists of a list of numbers, that indicates how many of the repeat units or STR's are present at different locations on the genome. Twenty different STR marker regions, throughout the genome, are used to create a DNA profile. Each STR marker region will have two numbers associated with it, one for each allele. Therefore, 14 numbers in total will be generated to create a full DNA profile. Scientists will then enter the DNA profiles into law enforcement DNA databases as 20 pairs of numbers and look for a match between evidence collected at the crime scene with that from the suspect.
DODI: It's funny and with shows like CSI, I feel like DNA profiling has been around forever, but this is still pretty cutting edge. What does Kathryn say about that?
KATHRYN LAMERTON: DNA profiling technology has grown so advanced and become so sensitive, that nowadays a simple touch can link someone to a crime scene. Investigators can now retrieve DNA profiles from skin cells left behind when a criminal merely touches the surface. So not only has DNA analysis got much faster, and more sensitive since Alec Jeffreys' run with the first samples, this moving out of the lab to increase the speed of forensic DNA testing, scientists have built an instrument that can copy and analyze DNA samples taken with a cotton swab in around 90 minutes. At the end of the process, the system will automatically interpret the data to create a DNA profile. This instrument is small and portable, and it can be located outside of the lab, so in police stations or at airports. So also, these instruments can be used by non-technical people.
DODI: All right, so all's well that ends well. And now crimes are solved with the help of DNA testing. And let's go back to that Las Vegas case that we mentioned at the start of the show.
CONOR: Yeah, and this is very much a case of what goes on in Vegas doesn't stay in Vegas.
DODI: Thank goodness.
CONOR: Yeah. Vegas law enforcement says that they solved the 1989 murder of 14-year-old Stephanie Isaacson using the smallest known volume of DNA ever. Investigators managed to send just 0.12 nanograms of DNA and...
CONOR: Exactly. So literally about 15 cells worth to a lab to help find a match. Just for context, your home DNA test kit that you use for Ancestry and that kind of stuff collects at least 750 nanograms, right?
CONOR: So, an order of magnitude, two orders of magnitude, more. So, the lab uses the sequences to comb through Ancestry™ databases, and pinpoint the suspects cousin, and identify a culprit who turns out to have died in 1995.
DODI: Wow. So now we are looking at the possibility of solving hundreds of cold cases where samples were previously thought to be too small to be usable.
CONOR: Perhaps so. And DNA has other fantastic features too, of course, not just for solving murders.
DODI: Okay, tell me more.
CONOR: Well, for example, by looking at our DNA, you can see why and where some diseases are hereditary. A few biopharma companies can use our DNA to create new medications for diseases maybe such as Alzheimer's or cancers.
DODI: So, in finding a perpetrator of a crime, DNA profiling can be used to see the similarities between two DNA samples. But outside the crime world, what you're telling me is that companies look at differences between DNA to find out if a person is carrying a hereditary disease?
CONOR: Yes, exactly. And you don't look at the same things as you do when you're investigating a crime. But DNA really has the power to tell us a lot about who we are, and what we can expect, such as hereditary diseases, or what we've done, such as in crime cases.
DODI: Wow. Just from those four molecules: ATCG.
CONOR: I know. Remarkable.
DODI: It is. Well, thank you for the crime story, Conor. And thank you to the audience for listening to our true crime homage on Discovery Matters. My name is Dodi Axelson.
CONOR: And my name is Conor McKechnie.
DODI: This podcast was produced by Olivia Stille our summer intern, and Olivia good luck at school next year. Music by Thomas Henley and a big thanks to our actors Sophie White, George Baxter, Antonio Donadio and Rebecca Payne. Now get back to your real jobs. Finally, thank you, Kathryn Lamerton for teaching us more about forensics and DNA fingerprinting.