What's Your Reaction?
Forensic Science: Fact or Fiction
Response by: Professor John Cassella
Imagine the scene… a serious crime has occurred in a city centre in the United Kingdom. Blue lights are flashing all around as Ambulance staff deal with the injured and the Police secure the immediate environment and collect witness statements.
So far so good – but here is where it gets fanciful. A ‘Hummer’ draws-up and out steps an individual clad in a protective white suit, with a gold badge hanging around their neck. A large gun sits holstered at their side and a swab is in their gloved hand, ready to take the first blood sample.
For many crime TV aficionados, this does not seem too far ‘off base’ as they are used to the decades of crime-science programmes such as ‘NCIS’ and ‘CSI’ in the US and ‘Waking the Dead’ here in the UK.Solved within the hour
As time passes (and usually within the hour), a myriad of evidence samples have been collected (not unusually numbering in to the tens or hundreds). Many thousands of digital photographs have been taken of every speck of dust at the scene and digital devices have been interrogated; whilst fingerprints and DNA analyses are not far behind. The only aspect that seems to be done ‘back at the lab’ is the post mortem!
Now, don’t get things out of context – forensic science as a profession and a career, is both fascinating and exciting in equal measures. But forensic scientists become experts in only one field and the work they do can be truly painstaking - taking many hours, on each item of evidence.Creating the ‘super scientist’
One of the myths of television crime shows is how they take the job descriptions of approximately five different forensic specialists and combine them into one to create a 'super scientist', a person who is able to solve any type of crime almost entirely on their own. In reality, a forensic science laboratory is divided into many different sections which all have different specialists working within them. One piece of evidence is usually passed through a number of sections before deciding if the collected evidence reveals anything of significance to the investigating Police team.Quality and quantity
The quantity of evidence is often as critical as the quality. Certain laboratory procedures, such as gas chromatography (which analyses the final composition of a piece of evidence in a gaseous form), require that piece of evidence to be destroyed in order to test it. In those cases, investigators must retrieve a usable amount of evidence from the scene. Too little evidence is as unhelpful as having no evidence at all.
Forensic science labs (euphemistically called Crime Labs) work in concert with law enforcement officials to ensure that work is done in a timely manner. There is usually a sizeable backlog of casework, and just one high-profile case can complicate the schedule even further.The reality behind the technology
Crime science TV viewers might (rightly) think that the forensic science fraternity has access to the most advanced technology available. For example, in one programme on TV an investigator plays with software that, according to the actor describing it, takes surveillance video and analyses it for characteristics such as facial expressions to determine whether the person is shy, anxious or even deceptive.
In another programme, one of the laboratory scientists pulls-out a handheld device that instantaneously pulls up a suspected criminal's photo along with his entire ‘rap-sheet’. The reality is currently quite different, which is not to say that the technology is not in existence, but is still being tested by the UK Police services; it isn't graphics intensive and interconnected, meaning that databases with, say, fingerprint information would not be tied to one of these with photographs and ‘mugshots’.
Computer systems that many UK Police services have, that store a lot of information, can be 20 years old or more. Some of these are DOS-based, not Windows or Android. But then, the Police are interested in data, not the fancy things of the visual world of TV.Other aspects of real life science that differ wildly from those on your plasma screen:
- On TV, the results from DNA tests are available almost instantly. In real life, even the quickest DNA testing method, Polymerase Chain Reaction (PCR), generally requires hours to produce preliminary results. The more accurate Restriction Fragment Length Polymorphism (RFLP) method can take much longer to yield results.
- On TV, intact stray bullets are quickly retrieved from the crime scene. In real life, bullets often become severely deformed or fragment, and they must be removed from an object with exacting care, so that they won't be further damaged and become unusable as evidence.
- On TV, detectives often pick up a weapon with a handkerchief or by inserting a pencil into the barrel. In real life, the handkerchief might contaminate possible DNA evidence, and the pencil would potentially damage microscopic markings (rifling) inside the gun-barrel, making it difficult to match the weapon to fired rounds retrieved from a victim's body or a crime scene.
- When a TV investigator ‘lifts’ a fingerprint from a crime scene, a computer invariably comes up with a conclusive match to a suspect. In real life, automated fingerprint database systems only indicate the probability that a fingerprint may be a match, and often are calibrated to generate a list of possible matches
- On TV, forensic scientists pour caulk or similar materials like resin into a stab wound on a corpse; they let it harden, and then remove a cast of a knife. In real life, the soft tissue around the wound usually is carefully dissected, layer by layer, to create a three-dimensional representation.
- TV forensic experts routinely magnify and enhance blurry, dark photos or surveillance video images to reveal faces, license plates and other details. While computer-aided enhancement is possible, going to the extremes achieved by the fictional scientists would simply turn a digital image into an indecipherable pixelated mosaic.
One problem arising today in UK Courts is that juries expect to be bedazzled when selected and seated for jury duty.
They wait to be overwhelmed and impressed when the prosecution counsel produces large amounts of unequivocal forensic evidence and related scientific ‘whiz-bang devices’ to prove the defendant is indeed guilty.
When these “toys for boys” are not introduced (as they don’t actually exist in the main) it makes the jurors’ role harder and all the more important; this is the CSI effect.
So, the next time you watch a TV Police show in which science appears, remember that it is fundamentally useful to help answer questions.The start of a fascinating career Forensic Science at Staffordshire University is the start of a fascinating career in the field, which can really make a difference to people’s lives. OK, so you may not get the sunglasses, gold badge and the gun, but you will get one of the most varied and satisfying jobs possible in science today.
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