Forensic Breakthrough: Recovering Fingerprints on Fabrics Could Turn Clothes Into Silent Witnesses

Currently a new technique in fingerprinting is being researched by forensic scientist in Scotland. This new Technique would allow the fingerprint of a suspect to be lifted from an article of clothing, something that has not been done before. For the past thirty years a team located at the University of Abertay has studied fingerprints and this new method seems to be successful.

The process in which this is done requires the use of the elements Zinc and Gold. This is know as VMD or Vacuum Metal Deposition, however this process has been around for some time. Joanna Fraser, a forensic scientist currently studying this method explains. "The research uses fine layers of metals to display fingerprints people may have left on fabrics, something which is far harder to do with soft surfaces. The technique has been around since the 1970s and is used on many surface but was never widely used on fabrics.”

I think that this new technique of fingerprinting can greatly help in the field of forensic science as well as law enforcement when it come to catching criminals.

http://www.sciencedaily.com/releases/2011/01/110131073141.htm

Solving Cases with Technology: Voice Stress Analysis

Voice stress analysis more commonly known as VSA is a very effective way to determine if someone is lying. It is designed to measure the changes caused by how the body reacts to stressful situations. The foundation of VSA technology is that a person’s voice emits detectable fluctuation in both AM, amplitude modulation, and FM, frequency modulation, frequencies called microtremors. When you listen to a person speaking, you hear the AM which rides atop the FM, which is undetectable to the human ear. Under the stress created from a deceptive response there is a reduction in the FM frequencies causing the microtremors to increase. It is an involuntary autonomic response detectable with a microphone and a computer running the proper software. The skilled examiner then analyzes the person’s voice patterns looking for these frequency discrepancies. Since this the change in frequencies is an involuntary response there are no known counter measures. A person cannot manipulate his voice frequencies the way he may be able to manipulate blood pressure, breathing, and skin response. 

When compared with a polygraph, the VSA technology is easier to use, faster to administer, less stressful, cheaper, and 98% accurate. VSA works in any language whether the subject is face to face or on the phone. Drugs, alcohol, and medical conditions do not affect the tests. Voice recordings that are years old can be used to solve cold cases. This test is less stressful for the subject than a polygraph test which makes VSA more accurate. When compared with a polygraph, the VSA technology is easier to use, faster to administer, less stressful, cheaper, and 98% accurate. A VSA test is more effective than a polygraph test because polygraph tests can’t analyze a recording while a VSA test can. Each test has the same admissibility in court.

http://www.forensicmag.com/article/solving-cases-technology-voice-stress-analysis?page=0,2

Forensic Breakthrough: Recovering Fingerprints on Fabrics Could Turn Clothes Into Silent Witnesses

          Recently, new research has been done on new methods of techniques of recovering fingerprints from different surfaces, the most challenging being from fabrics such as clothing recovered from a crime scene. Now it is the first time in about 30 years that recovering fingerprints from fabrics has become a major focus in research. As part of the research project, VMD, a technique known as vacuum metal deposition, uses gold and zinc to recover the fingerprint mark that is supposedly on the fabric. VMD is a highly sensitive method to easily detect fingerprints is already used on materials such as plastics and glass. When supposed fingerprints on fabrics are dusted with a combination of gold and zinc, the fabric is laced in a vacuum chamber, where the gold is heated up which results it to evaporate and spread a fine film over the fabric. Then when the zinc is heated up, it attached to the gold where there are no fingerprint residues. This helps reveal the fingerprint, where contact has been made you see the original fabric, and where there is no contact we're left with the gray color of the metal film. One way of explaining it is like a photographic negative, where colors show up as their opposites. Here the fingerprint ridges show through as clear fabric, but where there are no ridges we see the distinctive grey colour of the metal.

          The University of Abertay Dundee and forensic experts are currently studying its use in the examination of clothing and see if this evidence could act as a "silent witness" and bring value to an investigation. As research continues, recovering fingerprints have been successful on a number of other fabrics besides cotton, such as silk, nylon, and polyester. In the past, it was proved difficult to distinguish a clear fingerprint on fabric, but it is shown that it is now possible. Further research on this method will further improve the method itself and prove its effectiveness.

http://www.sciencedaily.com/releases/2011/01/110131073141.htm