[MUSIC] Well, first I'd like to show you that when you touch an object and someone will leave fingermarks on this object, the conditions in which fingermarks will be deposit may change, and may be quite complex. So I show you the situation that never happen in case work is that someone touching this object, with your hands laid down very quietly on the object, and that would leave marks undistorted, in pristine condition. The reality of things is very different. People will grab this object like this. And as in the case we'll discuss, that object was recovered As a little bag and you can crush it like this. In these conditions, when you touch an object, the shape may be different, distortion may occur. Finger may twist or provoke movement and hence the marks would be much more complicated. Complicated to the point that you may have multiple impressions of the same fingers, of different fingers overlay on top of each other. Or, as in this case, you may have one finger touching the surface on two different positions leading to marks which will be in different pieces. So all this makes that marks laid on surfaces are always complex, depending on how they have been laid down and the nature of the object that will receive that mark. So the first examination that is done systematically on any object on which we want to detect fingermarks is to use optical examination and to spend some time looking at the object under various conditions. To see if some marks can be detected, and at the same time, if any other pieces of information, traces could be seen and preserved. And that will be done typically in a forensic laboratory using a powerful lamp as this one. So this lamp is offering a powerful output in white light. And then you can put in front of the light selected filters that define wavelength. And that allows you to cover and to explore the object from UV up to the infrared or close to the infrared. And I will start with white light as usual. And good practice is to observe your object in white light. Now, in white light, and that will not be very obvious on this object, but on smooth objects, you may detect fingermarks just by looking at it and changing the angle of the light coming to the object. That will allow you to detect the mark without any detection technique, any chemical detection technique, but just by playing through interaction between light and surfaces. Then the next stage is to move from various wavelengths. And here I'm going into the UV, and I need to switch off the current light. And under UV, not only sometimes fingermarks may be detected because they had been left in some medium which will be luminescent in UV. But you will see other things, such as dust, potentially fibers, or other stains, which might be of importance to be collected, and that will be done. And then you will move up the wavelength. And potentially, doing examination in fluorescence mode, by one wavelength on the object and observing it at a higher wavelength with the goggles, like I do at the moment. And that will allow you to detect marks which may be fluorescent under these conditions, and they could be detected straight away and recorded. So that would be part of standard examination practice. We call this optical examination before any other technique is applied on the object. So I'm going to present to you another tool among our optical detection technique. And this tool is looking at marks in the UV range. So still on our object, on which, at the naked eye, we cannot see any fingermark, we'd like to observe this surface in reflection in the UV. So your eye is not sensitive in the UV. To do this observation you need two things. One is a light source in the UV like this one, and that light source is sending on the surface UV light at 254 nanometer. On the way back, the sensor, which is up here, you need an optical device which allows the UV to get through. It's typically a quartz lens, and the quartz lens will allow the UV to be reflected, go through the lens and impact the sensor. And the device here is ultra sensitive camera which allow you to see in the short range UV. So with that system, we can directly monitor on the screen, because your eyes will see nothing, but you can monitor on the screen how your potential marks may be visible on this surface, by changing the angle of the UV light on the object. And by moving the object from one section to the other, and its a bit time consuming, you will detect marks, marks which will not be visible with the bare, naked eye, and will only be visible in the UV. These marks can be recorded, directly. Now, one word of caution, because of UV light, UV is detrimental to DNA. So typically, that type of examination, like most of the examination we showed you, will be done after all the protective actions regarding potential DNA has been made. And an object like this one should not be submitted to long exposure to UV for a long time, otherwise potential DNA traces will be degraded. So here you are in the chemical detection laboratory for the detection of fingermarks. It's a laboratory equipped with all the detection techniques to detect marks. The choice of a technique is as a function of a type of surface. Here, we are dealing with plastic bag. This is with blue plastic bag, very similar to the bag that we had in the case in Madrid. That bag is a smooth surface. It went through all the optical examinations that we have done together. And the next step is to expose that surface to vapors of super glue. Now, the Japanese discovered at the end of the 70s, that when you expose the surface to vapors of super glue, the super glue has a tendency to come and stick to the ridges of the fingermarks, and it will polymer on that section. So when you leave an object under the vapors of super glue under quite restricted conditions in terms of humidity, but the glue will stick and we use the term gluing. Will glue the fingermarks on the object and they can be detected that way. So we will put the object alongside with what we call the positive control and on that piece of glass we lay down marks which we know are present. And then we follow the object during the whole process to act as a positive proof that the technique operated properly. So the cabinets we'll use is a specific cabinet which gives you the opportunity to hang objects in it, and I will hang the positive control, and then I will take the two pieces of interest. And they are just placed here. The cabinet offer an environment in which we can vaporized super glue, which is very similar to the super glue you can buy for homework, the vapors will be distributed in the entire cabinet under controlled humidity. And the vapors will come and adhere, polymerize we say, on the fingerprint's ridges. We will control this in time, because if you've over-developed, you will cover the whole surface by the glue. So under strict conditions, we will find the appropriate timing to detect the marks. Now, we need to prepare the glue now. Now, the super glue technique we will use for this is quite recent. It's called Lumicyano, which is a luminescent type of super glue. To do this, we will put in this little tray, standard super glue. But mixed with a powder, and the power has a dye which is luminescent. So instead of having a white deposit on the surface, we'll have a white deposit on the marks. But at the same time, this deposit will be photoluminescent as you'll see later. And the marks will be immediately visible under UV light in one step. So it's a one step process which give the gluing, plus the dye to allow examination under specific lighting conditions. So we'll go and weight this. So like in all forensic laboratories, all techniques, all validated techniques, are in a standard operating procedure, which the analyst will follow all the time. So for this case for the super glue cabinet we are using, I need to weigh 0.1 gram of powder and 2 grams of the super glue itself in that tray, and that will go into the super glue cabinet. So now we are ready to start the fuming process. The items are in with a positive control, and we have a super glue that has been prepared with a dye, so we are ready to run, and we will simply start a cycle. A cycle will be first humidify your chamber, then to super glue, and finally to purge the atmosphere so we can go back and observe the item. So we are back after the super glue fuming. Here we will first check that the positive control detected properly. As you can see, we have two marks that have been dev locked. Using this we can visualize them directly. Under UV light it gives a reddish fluorescence, which is what we're going to detect and hopefully you have a photographic apparatus with a macro lens which allow a recording of the marks. So we will look at the piece of evidence, check if any mark has been detected. If a mark is detected, we're going to mark it around the mark of interest, and we will put a small tape with which bear a ruler to make sure that we can control the size of the images. And then we will image them on the A part of the photographic system that we have here. So that concludes the sequence of detection that has been used, in fact, in the real case involving this plastic bag recovered in Madrid. We have been through the super glue fuming, the fluorescence examination, and that led to the mark that will be searched by the FBI on the large AFIS system. So that will conclude our detection as well. And the next stages would be to take these marks and compare them against prints of individuals. [MUSIC] [MUSIC] [MUSIC]
