Page 13 - Prescription for Crime Drug Testing

At scene of an automobile accident where classifying blood into various types. His work was
intoxication is in question, drug testing is extremely a starting point for many scientists and physicians
important. A sample of blood may be obtained for in the advancements of developing tests to use
testing, and compounds within blood samples are blood samples in criminal investigations. With these
often easily identified. A newer form of analysis advancements, Edmond Locard of the University
involves testing hair samples for intoxication or other of Lyons in France determined that a special crime
drug use. A hair follicle test will reveal intoxication laboratory was necessary. Locard, thus, established
immediately, and a strand of hair may retain this lab in 1910, and became known as the ‘Sherlock
evidence of drug or alcohol use for at least three Holmes of France’.
months. Laboratories that perform these tests are
operated by forensic scientists that can interpret the Following Locard’s lead, August Vollmer set up an
results of tests performed on controlled substances, American Police crime laboratory in 1924. Following
clandestine samples, and pharmaceutical laboratory this, the Federal Bureau of Investigation, founded in
samples. Without interpretation these results have 1908, set up a forensic crime laboratory in 1932. In
little value, and this interpretation is often written the years since, few changes to the methods used in a
into a formal report that can be used as evidence in chemistry laboratory to identify unknown substances
a court of law. Additionally, the forensic scientist is have been made. One drastic change, however, has
frequently asked to give expert testimony in court been influenced by the now widespread availability
regarding these analyses. and convenience of testing methods. For instance,
many companies now distribute drug screening
The history of forensic drug testing and analysis kits to law enforcement agencies that allow them to
dates back nearly 200 years. In the 1830’s a take a number of different presumptive screening
Scottish chemist by the name of James Marsh was tests out into the field for quicker results. These
summoned to aid in a murder trial. The suspect, kits, relatively easy to use and widely available, allow
John Bodle, was believed to have used arsenic- for more decisions to be made in the field without
laced coffee to kill his grandfather. James Marsh delay and have reduced the number of unnecessary
had been working to develop a chemical test to samples being sent to forensic chemistry laboratories
reveal whether or not a sample contained arsenic. for analysis. Also, the advancement of certain
His original test involved mixing the sample with technologies, such as gas chromatography-mass
hydrogen sulfide and hydrochloric acid, but, while spectrometry, now give results that are more
able to detect arsenic in the sample, the results accurate and specific than previous testing methods.
had deteriorated by the time he presented it to
the jury. This left reasonable doubt in the minds of The work done by forensics experts varies from
the jurors, and Bodle was acquitted of the murder. caseto-case, however there are two main categories
After this trial Marsh developed another chemical of tests that must be used to properly identify
test that detected arsenic at a more sensitive an unknown substance: presumptive tests and
level. In this test sulfuric acid and arsenic-free zinc confirmatory tests. When the exact identification
combined to produce arsine gas. Marsh discovered of a particular substance or drug is in question,
that when this gas was ignited it decomposed presumptive screening tests (sometimes referred
leaving a metallic arsenic residue which would not to as preliminary tests or spot tests) are completed.
deteriorate with the passage of time. This allows for a quick, initial identification or
exclusion of the substance. To perform preliminary
In 1901 the Nobel Prize was awarded to Karl testing, drug experts must have an idea of what
Landsteiner for his work in identifying and they are testing so that they may choose the

THE MYSTERY OF LYLE AND LOUISE 13