Los mitos de las series policiales

by Dan Skantar
Ever since the first episode of CSI, forensic dramas have become a staple of prime-time television. These hugely popular programs follow a common formula—uncanny investigators sweep a crime scene, extract the evidence, run lab tests and crack the case—all in a tidy TV hour.
While TV has thrust forensic science into America’s living rooms, it has also glamorized, exaggerated and oversimplified the field. In truth, forensic science is far removed from what you see on the tube. It is a painstaking, complex world of backlogged cases, cramped labs and squeezed budgets. Facilities, equipment and staffing are too often inadequate for the workload. The pressures to work quickly and with unerring accuracy are intense, because these labs serve a criminal justice system in which a life can be forever altered by the analysis of a single drop of blood or strand of hair.
TV writers don’t let technical accuracy interfere with a good story. A taut drama that plays loose with the facts may captivate the viewing audience, but it frustrates forensic professionals. What people see on TV affects their view of actual police science. As former Los Angeles Sheriff ’s Department criminalist Elizabeth Devine, technical adviser to CSI, says, «Nobody chalks bodies.» The real world of the forensic scientist «can be tedious,» admits Katharina Babcock, a forensic scientist for the State of New Mexico. «You have to be patient, and you have to pay attention to every detail.»
Glitz or grit? Let’s explore the hidden truths of forensic science—and debunk a few TV-inspired myths. But first, what exactly does a police scientist do?
A forensic scientist performs two critical roles—as analyst and as witness. The scientist examines physical evidence found on a victim, at a crime scene, or both, and compares it to evidence found on a suspect. He or she also provides expert testimony in a court of law. A forensic scientist must have the skill to examine the tiniest piece of evidence from a crime scene plus the cool and competence to clearly and confidently defend the findings under oath in court.
MYTH No. 1:
TV crime shows focus on a few central characters that become, in effect, super scientists capable of handling all types of analysis. «They’ve taken four or five (investigators) and made a composite of them, then dramatized it,» says Robert Fraas, director of the forensic science program at Eastern Kentucky University.
In reality, forensics is a specialized realm comprised of half a dozen or more distinct departments. For example, the Sheriff ’s Lab in San Diego, CA consists of 55 staffers and nine different sections such as Firearms, Controlled Substances, and Fingerprints (see sidebars). Evidence is typically passed through multiple sections for examination. The scope of the science and the knowledge and experience required has forced specialization into the crime lab. According to nationally renowned forensic pathologist Dr. Cyril Wecht, «There are no generalists in the world of modern-day forensic science to rival Sherlock Holmes and Quincy.» And, unlike on TV, you won’t see genuine forensic scientists eating in the autopsy lab or making arrests.
MYTH No. 2:
Whether it’s a smudge of dirt, a broken fingernail or something more exotic, TV sleuths always get their evidence, right? After some careful fine-tooth combing, the crime scene reveals all.
The truth is, even the most secured crime scene may not surrender its secrets easily, and often the evidence is found in insufficient quantity or is unusable. Fingerprints are one example; TV’s «lab boys» have been successfully dusting for prints since the days of Dragnet. While modern techniques such as computer imaging have made fingerprint analysis more sophisticated, technology cannot create evidence that doesn’t exist. Dr. Wecht says, «Finding identifiable fingerprints that can be developed and are of sufficient quality to do an automated search are more the exception than the rule.»
The quantity of evidence is often as critical as the quality. Certain lab procedures like gas chromatography require a 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 bad as having no evidence at all.
Evidence gathering is an exacting process that cannot be rushed, but even the finest forensics teams find themselves in a never-ending race against the clock. All too often, hard evidence is perishable and can be degraded or even destroyed by weather or other natural forces over time. Fresh tracks mark the best trail, and how soon a crime scene is discovered can be the deciding factor in solving a case.
To fit a story into one hour, Hollywood writers take liberties with the laws of science, especially the compression of time. TV makes analysis seem as fast as baking a cake. Real crime labs don’t work so swiftly. First of all, in many labs cases are handled in the order they are received. Normally, it takes weeks or months for evidence to hit a benchtop. When a case reaches the lab, the evidence may be routed through a sequence of specialized labs. For example, a paper document might be analyzed for fingerprints in one lab and later tested for its authenticity in another.
Crime labs work in concert with law enforcement officials to ensure that work is done in a timely manner. There’s usually a sizeable backlog of casework, and just one high-profile case can complicate the schedule even further. Cases in which lab results are needed to make an arrest are given priority, as are cases headed to trial. According to Susan Scholl, director of the New Mexico state crime lab, managing the demands of prosecutors «can be a real juggling act.»
Also shattering the myth of instant results is the fact that the laws of science don’t bend. Analytical physics and chemistry procedures require a set amount of time. Factor in repeated tests and inconclusive data and it is easy to see how long the process can be before achieving definitive results. (Chemical analysis may take weeks to separate and identify all the compounds in a corpse.)
The scientists must collect all the test data for a given case, put it together and draw conclusions. It’s a collaborative process, but a time-intensive one, too. The smallest nuances matter.
The laboratory set of a TV crime drama is a forensic scientist’s dream—outfitted with enough high-tech gadgets to rival the Batcave. A criminalist watching at home might wince at all this opulence while she’s stuck wrestling every day with a beat-up old centrifuge. In reality, crime labs are often underfunded. They fight for precious budget dollars against other higher-profile municipal departments like police and fire. Historically, crime labs have toiled in relative obscurity at the bottom of the funding totem pole, often relegated to leftover office space, or forced to use worn-out equipment.
Shortages aren’t limited to square footage and equipment. Labs battle each other to hire and retain qualified professionals. Relatively few universities provide structured forensic science curricula, but the field has attracted a majority of female students at many schools—80% at Michigan State and 70% at West Virginia (1999). Aside from a formal forensic program, newcomers enter the field from a wide range of scientific disciplines.
New lab design incorporates economy of space, ergonomics, and workflow to meet current and future needs. The goal is improved efficiency as the demands on the forensic lab continue to grow. Ken Mohr, a principal at the design firm of Health, Education + Research
The Crime Lab Staff
A peek inside the San Diego County Sheriff ’s Department Crime Lab reveals a staff of 55, headed by a civilian Crime Lab Manager:
Lab Manager (1)
Supervising Criminalists (4)
Criminalists (28)
Latent Print Examiners (7)
Document Examiners (2)
Lab Assistants (2)
Clerks (4)
Administrative Analyst (1) Forensic Computer Specialist (1)
Forensic Evidence Techs (5)
Associates, says that, «DNA-driven work, estimated between 10 to 20% today, is on the rise.» Mohr adds that to meet this burgeoning caseload, more and more labs are introducing robotic systems to automate procedures in an effort to achieve higher productivity.
A forensic lab faces all of the requirements of a conventional lab plus the elevated standards applied as an adjunct of the judicial system. The lab must meet environmental health and safety regulations and operate efficiently within budget constraints. It bears the added burden to secure and preserve evidence in an uncontaminated state. Accuracy is paramount since test results, presented before a jury, can determine a defendant’s fate. As Mohr states, «The technical work performed in forensic labs must withstand evidentiary challenge.»
So what can we make of forensic science on TV? Admittedly, it’s compelling entertainment, but the word entertainment is key. The real stars are the tens of thousands of forensic scientists who will never find themselves in front of the camera, working in labs across the country, applying science and technology to keep the scales of justice in balance.
Crime labs typically consist of a number of separate labs, each devoted to a different branch of forensic science. Here’s a look at the San Diego Sheriff ’s Crime Lab:
Section Purpose Common Samples or Sample Sources Typical Methods
Trace Evidence Examine small samples for unique characteristics Fibers, hair, flammables Chemical, physical and microscopic analytical methods.
Controlled Substances Identify suspected illegal drugs for type and amount present Pills, powders, vials, syringes Chemical, physical analytics
Forensic Biology Examine physiological fluids/stains for genetically determining factors: blood type, species Blood, saliva, other body fluids and tissues DNA analysis
Forensic Alcohol Analysis for alcohol in DUI cases Blood, breath or urine samples from arrestees Automated gas chromatography, infrared spectrophotography
Forensic Toxicology Analysis of blood and urine samples for presence of drugs or poisons DUI and controlled substance arrests Gas and thin layer chromatography
Firearms Examination of firearms for class or individual characteristics Handguns, rifles, shotguns, shell casings, bullets Chemical and physical analysis, comparison light microscopy
Fingerprints Examination of latent (not visible) fingerprint impressions for characterization and ID Any evidence with a surface that can accept a fingerprint impression Powders and chemicals used with light sources to visualize print
Automated Fingerprint Retrieval Compares unknown prints from a crime scene to database of known prints Same as above Visually magnified comparisons and computer-aided scanning of evidence
Questioned Documents Resolves questions concerning age, content or authenticity of documents Counterfeit documents, forged checks, anonymous letters, suicide notes Light, infrared and UV microscopy
Dillon, Hal; Forensic Scientists: A career in the crime lab, Occupational Outlook Quarterly, Fall 1999
McClannahan, Rory; Shorthanded crime lab bogged down with work, ABQJournal.com, March 27, 2003
Johnston, John; TV fuels interest in forensic science, The Cincinnati Enquirer, May 7, 2002(www.enquirer.com/editions/2002/05/07/tem_tv_fuels_interest_in.htm)
Kluger, Jeffrey; How science solves crimes, Time, October 12, 2002 (www.time.com/time/nation/printout/0,8816,364313,00.html)
Wecht, Cyril H.; Science fiction: TV programs fail to show busy, overworked forensic labs, Harrisburg Patriot-News, May 4, 2003, p. D3 (www.law-forensic.com/cfr_gen_art_9.htm)

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