Skip to 0 minutes and 5 secondsFingerprint is a byword for identity and identification. It is widely used in everyday language to refer to a set of characteristics that define an object, activity, or even a style, in some cases. Human identity is central to the criminal justice process. Fingerprints are routinely used in most countries around the world to check that an individual who is arrested is who they say they are and if they've come to police attention previously.

Skip to 0 minutes and 38 secondsAs well as incriminating individuals, fingerprints are routinely used to eliminate individuals from criminal inquiries and to identify victims of mass disaster and terrorism.

Skip to 0 minutes and 51 secondsThey are also used as a means of identity in non-criminal situations, such as general security in buildings and access to computers. Fingerprints arise from a particular type of skin called friction ridge skin, found on the fingers and palms of the hands and soles of the feet. The origin of these patterns is genetic and they develop in the foetus in the womb. However, identical twins, who have identical DNA, have different fingerprints. So fingerprints are also influenced by non-genetic factors. The patterns of ridges and furrows can be transferred in sweat and other substances to items when they're touched. For example, when picking up a drinking glass.

Skip to 1 minute and 40 secondsThese skin patterns that form fingerprints persist throughout life, providing a powerful biometric that can be stored in databases. There are records from around eight million individuals stored on the national database in the UK. That's 80 million individual fingerprints. Many other countries will have equivalent numbers of records. Fingerprints are perhaps best known as a means of linking individuals to a crime scene or an item, such as a weapon, or a vehicle that was involved in a crime. Despite the widely known fact that transfer of fingerprints can be easily prevented, they are still found at crime scenes around the world every day. There is an important convention in the use of fingerprint terminology in the UK.

Skip to 2 minutes and 33 seconds"Fingerprint" refers to an impression taken from an individual as a record. Impressions recovered from crime scenes are referred to as "fingermarks". A similar distinction is made in other countries, although the terminology is different. In many countries, recovered marks are referred to as latent prints. This is an important distinction between circumstances where the source of the impression is known and those where it is unknown but can be inferred following examination. The oldest and most common method for recovering latent prints is the use of fine powders, which are applied by a brush. Finely-powdered aluminium, the most common one used, adheres to the fatty components of the residue. Powders have the advantage of simplicity and ease of application.

Skip to 3 minutes and 36 secondsThere is a wide range of other techniques that can be used for the detection and visualisation of finger marks, which depend on the nature of the surface on which the mark is deposited and the components in the residue of the mark.

Skip to 3 minutes and 52 secondsLasers and ultraviolet light can be used to promote fluorescence of marks, which can then be photographed. Marks can also be enhanced by a range of chemicals that react with specific components in the residue. Finally, we should note that fingerprint examination in many countries is under scrutiny and subject to major reform. Why this has come about is complex and will not be covered in this module. But you may encounter some of these issues in your personal research or perhaps are aware from cases in your country. Suffice to say that in recent years, there have been a number of troubling misidentifications involving fingerprints. And these have exposed weaknesses in fingerprint methodologies and training.

Skip to 4 minutes and 43 secondsAmongst the best known of these cases are the Shirley McKie case from Scotland and the Madrid bombing from the United States.

Skip to 4 minutes and 54 secondsDespite these current issues, fingerprint examination remains one of the fastest and most reliable means of human identification.

Welcome to Week 2

What we’ve looked at so far should have provided you with a solid introduction to crime scene investigation, the process and practices involved and the roles and responsibilities of those who undertake such investigations. We also introduced the concept of the 6Ws and we will refer back to these during the rest of the course.

Now we are going to change pace a little and provide some more technical information over the next four weeks of the course during which we will explore fingerprints, DNA, tool marks and drug analysis. Within most weeks we have linked to external documents and reports as well as some YouTube videos, all of which are there to help you with your learning.

Each week will also have an update of the Murder by the Loch so that we can continue to discuss the impact (or otherwise) of these evidence types as our case unfolds. In week 6 we will discuss the case in more detail and work with you to demonstrate how we can use what you have learned to begin to pull the strands of the investigation together. We will also be asking you to use what you have learned across the course to evaluate the prosecution and defence hypothesis for the Murder by the Loch and vote on the final outcome!

This week we’re going to concentrate on fingerprints, what they are and how they are formed, how they are recovered and how they are examined and interpreted. The resources (in the ‘see also’ resource sections) which we will direct you to are sometimes quite large reports and these might appear quite daunting at first! Don’t be put off, we will direct you to specific pages and chapters of the reports that may help your learning of the topic, but we would also encourage you to explore these reports further if you wish. There are discussions to get involved in and a chance to take your own fingerprints and look at the features that are within them.

This week we will also be holding the first of our four course survey polls. The first survey poll relates to the recovery of fingerprints in our case. You will see the result of the survey poll after it is finished and we will discuss the results and your comments later on in the course.

Warning: Some of content presented in this course may be distressing to individuals, particularly younger learners. Notwithstanding, the material is representative of that encountered by forensic scientists and we have presented it in an objective and professional manner.

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Introduction to Forensic Science

University of Strathclyde