[MUSIC] Now that we've seen how diverse forensic science is and I've talked about the different units that may be present in a forensic science lab, let's take a look at identification and individualization. So one task for forensic scientists is identifying things. If something is found at a crime scene, can they answer the question, "What is it?" Now, sometimes this is going to be easy, simply by looking at it. Other times, this might need a battery of chemical or biological tests to determine what this item is and whether it's relevant, but after an item has been identified, then can it be classified? So this is class characteristics. These are characteristics that put an object in a certain subgroup or class. However, it doesn't mean we're going down to determining a single source for that object. An example, for instance, would be a shoe. A shoe is obviously a shoe, but what brand of shoe is it? What type of shoe is it? Is it a man's shoe or a lady's shoe? If you find a fibre at the crime scene, what kind of fibre is it, is it a cotton fibre, a wool fibre, a nylon fibre, et cetera. If you find a bullet at a crime scene, what kind of bullet is it? Particularly, what calibre bullet is it? So these are class characteristics and these start to narrow down the object in question. Now, ideally, what we want to get to is individualization. That is where you start from a classification and you narrow it down to one. So you identify a brand of shoe and then you narrow it down to a particular person's shoe. This, of course, is not always going to be possible but it's something that we strive to do. So for a physical object, for instance, such as a shoe or an item of clothing, you might find out who is the manufacturer. If it's, for instance, a tool, you might look for the serial number and objects may carry fingerprints on them. If it's something of chemical origin, then you might look at trace elements or impurities within that object to do this narrowing down; and for biological samples, blood for instance, we will try to individualize it by using the blood type or by DNA analysis. Let's look at an example of individualization and the example we're going to take is the fairy story, Cinderella. So most of you will be familiar with this story from when you were small, and essentially, the story is that the Prince decided to have a ball. All the ladies, the young ladies in the town, were invited because he wanted to marry one of them, so he wanted to meet them all, but Cinderella couldn't go to the ball because she was too poor and she had nothing to wear. However, at the last moment, her Fairy Godmother appeared and by magic, provided a gown and a carriage and all that kind of stuff, and Cinderella could go to the ball and could dance with the Prince. And of course, the Prince fell in love with her, but the magic was going to expire at midnight. So just before midnight, Cinderella rushed out of the room before her beautiful gown turned back into her normal rags and, of course, the Prince had fallen in love with her but didn't know who she was. So he had to investigate and find out who this lady was. None of the eye witnesses were any use because none of them had ever seen Cinderella dressed like this before and so could not recognize her. So he could not rely on any eyewitnesses. So what did he do? He turned to Forensic Science. He has to examine any traces left by Cinderella in the ballroom, and as we know, she left a very significant trace. As she rushed out of the room, one of her shoes came off, and in the story, it is a glass shoe. Now this, of course, is very improbable, it's a ridiculous material to make a shoe of, but it does make a nice fairy story. The reason she's wearing a glass shoe, it has been suggested, that it is a confusion between the French word for glass and the French word for squirrel fur but, of course, you can't have someone in a fairy story wearing parts of a cute fluffy animal, so it's a good thing it's a glass slipper. Glass can be analyzed forensically very well. A lot of glass objects, of course, have some kind of code number or identifying number and the manufacturer's mark. So if it has that, you can then go to the manufacturer and find out who they sent those products to, which shops or vendors have those products and then from their records you could find who had bought those. Of course, this is a magic glass shoe, it comes from a fairy godmother, so that couldn't be done. You can also do a physical investigation of glass. One of the characteristics of glass is the density of the glass. So if you measure the density of the glass, you can find out what kind of glass it is, and then again, you can go to companies that manufacture those particular kinds of glass. In the fairy story, however, these techniques were not available to the Prince. So what he employed was a technique that we will see again in later lectures, when you come in a later lecture to the Peter Griffith case and also to the Colin Pitchfork case, you will see this technique being used. So what the Prince did was a mass screening of all of the people in the city. So first of all, of course, he can exclude all the men. So he only has to screen all of the women and, of course, only has to screen the young women. So he sent his officials with the glass slipper out to find a woman whose foot would fit inside and, of course, the only one whose foot fit it was Cinderella. So they got married and lived happily ever after. Of course, nowadays, we know that this technique of finding out whose foot would fit into the shoe is really not very good, and if you read up about what happened in the O.J. Simpson trial, and of course, if you watch the associated Seinfeld episode, you will know that this isn't a very reliable technique. And nowadays, of course, if you wanted to know who that shoe would belong to, you would try and get some DNA from the inside of the shoe and do a match in that way, but of course, that sort of technology wasn't available to the Prince. So there is an example of individualization of an object. The shoe left at the ball being individualized to be the shoe that belongs to Cinderella. So we come back to this idea of comparison leading to association. On the left is our crime scene that you saw before. On the right is our suspect, who again, you saw before. So evidence found at the crime scene would be compared to evidence found on the suspect and similarly, vice versa, and if those comparisons are successful, then you can associate that suspect with that crime scene. Now, we have said that forensic science is about reconstructing the events that happened in the past, and that is gaining an understanding of the sequence of past events, essentially so that you can tell the story of how the incident occurred. This, of course, is not the same as re-enactment. Re-enactment may be part of reconstruction, but re-enactment is taking it further, where you actually go back and you re-do one of the events. You might use re-enactment when the events include something that is beyond your normal experience, or where there's some special phenomenon that you want to test, and it's only by re-enacting it that you can be sure of what really happened. Re-enactment came in during the trial for the 2005 London bombings. So you may recall that on July 7th 2005, four bombs exploded on public transport in the city of London, causing great injuries and death. In fact, 52 people were killed in that incident. What is less well remembered is that two weeks later, there was a repeat event. Four bombs were detonated on public transport, but on this occasion, the bombs did not explode properly and the terrorists could be arrested. Now a couple of days later, a fifth bomb was discovered, and this bomb had been abandoned in West London, and it's from this fifth bomb that the forensic scientists were able to know exactly how these bombs had been constructed and what they were made of. And as you can see from the very simple diagram there, they included the detonator embedded in a quantity of home-made explosive. Now the five bombers are shown here, four of them who have actually attempted to detonate their bombs and one who'd abandoned his bomb, and there were numerous forensic links and CCTV evidence to show that these five people were the bombers. So when this came to court and the defense lawyers for these people had to come up with a defense, it was simply not possible for them to claim that these people have not been trying to detonate these bombs. So the defense they came up with was concerned with the motive, and the defense they came up with was that these bombs were not real bombs intended to kill and maim people and cause destruction. These bombs were just hoax bombs and that's why they didn't really explode. They were hoax bombs and it was just a protest of government policy. So really, the case comes down to Mens Rea - what was the intention of these people? Well, in the earlier section, we said that forensic science is usually not very good at determining aspects of Mens Rea, but in this case, it turned out it could, and it comes down to the question of the construction of the bomb. Were the bombs built for hoaxes, or were they really built in order to cause destruction? The fifth bomb enabled the forensic scientists to reconstruct one of these bombs and then do a re-enactment of the explosion. So clearly this wasn't a hoax. This was an intention to cause death and destruction. A much earlier example of re-enactment comes from the case of George Smith, and this is the famous "Brides in the Bath" case. Now Smith, it seems, had worked out he could earn a living by marrying women, stealing their money and murdering them. But his scheme came unravelling in 1914 with the death of his wife Margaret Lloyd, who drowned in her bath, leaving him 700 pounds of insurance money. And somebody realized that it had happened before - the same thing had happened before to Alice Smith in 1913, and to Bessie Williams into 1912, and all the women had died in the same way. They had been taking a bath and apparently, had had an epileptic fit in the bath and this had caused them to drown without causing any signs of a struggle or bruising on the body. Now if it happens once, it's believable, but when it had happened so many times, and it turns out that George Smith had married a total of seven women, there were suspicions. And the question comes down to, did those three women really drown accidentally in the bath due to an epileptic fit, or were they somehow drowned? Now, if someone's in the bath and you try to drown them by pushing their head underwater, they are going to struggle, and that is a violent struggle and that would lead a lot of bruising, and there was no bruising on these bodies. And then the idea came about that maybe Smith had used a very clever technique for drowning these women. And that is by grabbing their feet and pulling violently on their feet so that their head went very suddenly underwater, and the water would rush up their nose, and the suggestion was that that would cause rapid unconsciousness without any signs of a struggle. Well, how do you tell? Well, the man who called in to investigate this aspect was someone we met already in this course, Sir Bernard Spilsbury. And Sir Bernard decided the only way to test this theory was by re-enactment, so he got some lady divers to volunteer. They got in the bath, he pulled their feet, their heads went underwater, and sure enough, they rapidly became unconscious without any struggle. It was a very effective technique and it was apparently quite difficult to revive some of these volunteers afterwards. Fortunately, they were all revived. Of course, George Smith's victims were never revived, so George Smith was convicted of murder and he was sent to hang. Now your re-enactment, of course, is only going to be as good as the people doing the re-enactment. So this is a very curious case, which hinges on a re-enactment, and that is the death of Gareth Williams back recently in 2010. And it became a big story in the media, probably because of Gareth Williams' occupation. He was a cryptographer working for British Intelligence, and he was found in his apartment in August of that year, and he had been dead for nine days. When the apartment was investigated and when the body was examined, there was no signs of any struggle, there was no traces of poisoning, and there was no sign of asphyxiation. Now, where was the body found? It was in a sports bag like the one pictured, not a very big sports bag. It was padlocked, and it was padlocked on the outside, and it was in the bath. So if you look at the situation, then surely, Gareth Williams must have been locked in the bag by someone because the lock was on the outside, but how do you prove this? So some yoga experts were brought in to re-enact this scene, to find out whether someone could lock themselves in a bag and padlock themselves on the outside, and the yoga experts were unable to do this. So the coroner doing the investigation concluded that Gareth Williams could not have locked himself in the bag. However, if you go on YouTube, you can find another re-enactment of this situation, where somebody succeeds in locking themselves into the bag because they know the trick of how to do the padlocking. So what's the truth in the Gareth Williams case? Well, you go on YouTube, you can find the videos, you can watch them for yourselves and make your own decision. All I'll say is, please do not try this at home.