Forensics For Dummies. Douglas P. Lyle
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Название: Forensics For Dummies

Автор: Douglas P. Lyle

Издательство: John Wiley & Sons Limited

Жанр: Зарубежная образовательная литература

Серия: For Dummies

isbn: 9781119181682

isbn:

СКАЧАТЬ helped the Federal Bureau of Investigation (FBI) establish a national forensics laboratory that offered virtually every forensic service known to law enforcement across the United States. It, too, served as a model for future state and local labs. Now many states have networks of regional and local labs that support law enforcement at all levels.

The St. Valentine’s Day Massacre

      During the height of Prohibition, gang warfare raged over control of the illegal alcohol trade that sprang up in many U.S. cities. None was bloodier than the war between Chicago rivals Al “Scarface” Capone and George “Bugs” Moran.

      On the night of February 14, 1929, seven of Moran’s men were waiting for a shipment of hijacked liquor in a warehouse on Chicago’s Clark Street. Unbeknownst to them, the shipment was a setup orchestrated by Capone in an attempt to kill his chief rival, Bugs Moran. Moran was supposed to be at the warehouse, but he arrived late. When he got there, he saw a police car pull up and five officers enter the warehouse. Moran retreated and heard machine gun fire, then saw the five cops come out and drive away.

      The real police arrived and found that each of the seven men had been shot numerous times. They recovered 70 shell casings. Bullets later were recovered from the victims. Cardiologist Dr. Calvin Goddard, who became famous during the Sacco and Vanzetti case (see Chapter 20), was called in because of his expertise in firearms identification. He determined that the shell casings were from Thompson submachine guns. Using the newly developed comparison microscope, he tested casings from Thompsons belonging to police and determined that none of them were the murder weapons. Goddard’s findings meant that the killers had impersonated police officers. Suspicion fell on Capone. Police raided the home of one of Capone’s hit men, finding two Thompsons that later were identified as two of the murder weapons.

       Identifying common procedures

      Scientific services offered by modern crime labs and medical examiners’ offices are varied and complex. The number of services supplied by a particular laboratory depends on its size and budget. State and regional labs may provide a wide array of services, whereas local labs may provide only basic testing. These smaller labs typically outsource more sophisticated testing to larger regional labs. In addition, the FBI’s National Crime Lab offers services to law enforcement throughout the country. Not only does the FBI lab perform virtually every type of test, it also possesses or has access to databases on everything from fingerprints and tire-track impressions to postage stamps.

      Larger labs often feature separate departments for each discipline, while smaller labs tend to combine services, perhaps even relying on a single technician to do all the work. Obviously, in this circumstance, a great deal of the work must be sent to larger regional labs.

      Common procedures conducted in a crime lab include

      ✔ Fingerprint analysis (Chapter 5)

      ✔ Tool-mark and impression analysis (Chapter 7)

      ✔ Blood analysis (Chapter 14)

      ✔ DNA analysis (Chapter 15)

      ✔ Toxicological testing (Chapter 16)

      ✔ Trace evidence evaluation (Chapter 17)

      ✔ Firearms examination (Chapter 18)
From fiction to fact: Forensic scientists through the years

      The first forensic scientist came not from the world of science but from the world of fiction. Sir Arthur Conan Doyle’s character Sherlock Holmes frequently used the sciences of fingerprinting, document examination, and blood analysis to solve the crimes he investigated. In fact, in the first Sherlock Holmes’ novel, A Study in Scarlet, Holmes developed a chemical that determined whether a stain was blood.

      Similarly, Mark Twain employed fingerprint evaluation in two of his works (Life on the Mississippi and Pudd’nhead Wilson) nearly a decade before they became recognized investigational tools.

      The first real-life forensic scientist was Hans Gross. In 1893, he published the first treatise on the use of scientific knowledge and procedures in criminal investigations. Others soon followed.

      In 1901, Karl Landsteiner discovered that human blood could be grouped and devised the ABO blood groups that still are in use today. In 1915, Leone Lattes developed a simple method for determining the ABO group of a dried bloodstain and immediately began using it in criminal investigations. Today, ABO typing, though not able to absolutely identify a particular person, is used to exonerate some suspects, to refute paternity, and to reconstruct crime scenes.

      Early in the 20th century, Calvin Goddard perfected a system for comparing bullets under a comparison microscope to determine whether they came from the same weapon. And, Albert Osborn laid down the principles of document examination in his book, Questioned Documents, which still is used today.

Peeking Inside the Criminalist’s Toolbox

      Crime-scene investigators are charged with finding, collecting, protecting, and transporting all types of evidence to the crime lab. Although each person or team may have different ways of doing things, typical equipment and supplies they take to the scene include the following:

      ✔ Crime-scene tape to demarcate and secure the scene

      ✔ Camera and/or video recorder to document the scene and the evidence

      ✔ Sketchpad and pens for scene sketches

      ✔ Disposable protective clothing, masks, and gloves

      ✔ Flashlight-alternative light sources such as laser, ultraviolet, and infrared lighting for exposing certain types of evidence

      ✔ Magnifying glass, tweezers, and cotton swabs for collecting hair, fiber, and fluid evidence

      ✔ Paper and plastic evidence bags and glass tubes to collect and transport evidence

      ✔ Fingerprint supplies, which include ink, print cards, lifting tape, and various dusting powders and exposing reagents such as luminol

      ✔ Casting kit for making casts of tires, footwear, and tool-mark impressions

      ✔ Serology kit for collecting blood and other bodily fluids

      ✔ Entomology kit for collecting and preserving insect evidence

      ✔ Hazmat kit for handling hazardous materials

The Cornerstone of Forensic Science: Locard’s Exchange Principle

      

Every contact you make with another person, place, or object results in an exchange of physical materials. If you own a pet, this material exchange is well known to you. Look at your clothes and you’re likely to see cat or dog hair clinging to the fabric – a pain in the behind if you want to keep your clothes looking sharp, but an incredible boon for forensic science. You may also find that you transfer these hairs to your car, your office, and any other place you frequent.

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