If you’ve ever wondered what equipment the pro’s use when they’re cracking a case, then wonder no more. Here’s a round up of some top crime-catching gadgets …
All kitted up!
A standard forensic kit contains fingerprint powders and brushes. They’re for dusting all those telltale marks that get left behind, so that the prints show up. Once they do, special tape is used to lift the print off the surface, so it can be looked at later on. This is still one of the most effective ways of catching criminals, but what if you need something a little more sophisticated?
Lifting prints!
How about an electrostatic dust print lifting machine or ESDPLM? Just so you know, ‘Electrostatic’ is a type of electricity, that’s attracted to the surface of some objects – in this case it attracts the dust print from a shoe to our machine, leaving a perfect imprint. You can use one of these to retrieve the dust from shoe marks on floors, carpets and upholstery or wherever photography and other conventional methods couldn’t be used to get the prints….
Fancy footwork?
Shoeprints are important, because most crooks remember to wear gloves. But unless you can fly, it’s difficult to hide the prints left by shoes. “Treadmark” is the very latest in the recovery and analysis of shoe marks discovered at crime scenes. It’s a system that uses image technology. Thousands of images of suspect shoes have been captured and stored digitally. A computer can then automatically match prints found at the crime against the database… It can also make use of other elements for image-matching, such as lip and palm prints along with tyre track and tool marks.
One of the best ways to get a copy of a mark left by a shoe or a tyre in the mud is to use casting plaster. This will give an exact replica of the indentation made. Experts can then go away and match the marks to suspect’s tyres tracks or shoe prints.
Torn-out pages?
Imagine you find a notepad at the crimescene. Some of the pages have been ripped out of it. You’ve got no way of knowing what was written … or have you? An Electrostatic Indented Document Reader (EIDR) can help. This device is designed to apply an electrostatic charge to film held over a document by using a vacuum. Indented marks on the document are then developed on the surface of the film by powder. This process will show what was written on the pages above, and might provide vital clues.
Shedding some light!
At crime scenes, investigators require extremely good lighting to make sure they don’t miss anything… So forensic experts bring their own high intensity lamps with them.
The light fantastic!
A video spectral comparator enables the operator to view documents with different wavelengths of light, using normal, ultra-violet and infra-red, viewing the image via a digital camera with a choice of filters. It can also bring back writing that may have faded or been completely lost. You can look at the different colours of the inks and they can be recorded so you can compare them.
Sometimes normal light isn’t enough, so an ultra violet lamp is sometimes used to help illuminate the crimescene.
Ultra violet light sources can be used either at the crime scene or in the laboratory to look at several types of evidence. Many fluids that come from humans such as blood, saliva and urine fluoresce (glow) under ultraviolet light, as can other items such as hairs, fibres, fingerprints and even shoe prints…
Up close and personal!
Think you’ve got double vision? No, it’s just a Comparison Microscope. This is two microscopes which can be viewed simultaneously, usually with the image from one being on the left of the split screen and the other on the right. This is needed to compare fibres, hairs and paint fragments under the same lighting conditions and magnification.
Tried and tested?
Something else that can help you see a bit better is a trusty old, magnifying glass. These may seem like ancient technology now, but just because Sherlock Holmes used one in the Victorian era, doesn’t mean they’re not used by forensic experts today to examine fine details at a crime scene. For really small things, a hand-held microscope comes in handy. This hooks up to a laptop computer, and can be used on the spot.
Keep it clean!
It’s essential that forensic investigators wear the correct clothing when inspecting crimescenes. Otherwise you can contaminate evidence with fibres from your normal everyday clothes – in the same way that criminals can. This could ruin the whole investigation, so, the best thing to wear is a suit made of polypropylene, which is a special type of plastic. This material has another benefit too as it can also act as a defence against any hazardous liquids that happen to be present…
Thanks to Dr Carolyn Morton at the University of the West of England for the technical pictures used on this page (check out their site - its got loads more information).