Science for Cops
I admit it: I'm a Law & Order fan. I love watching television show detectives Lennie Briscoe and Ed Green trade wisecracks as they slip the cuffs on another homicide suspect. But, like millions of other fans, I've sometimes wondered how realistic the show is. In particular, I was skeptical of that stock scene (it occurs in nearly every episode) in which the geeky technician in the police laboratory uncovers a piece of evidence that blows the case wide open. Come on, I thought, how often does that actually happen? And are police labs really that technologically sophisticated? I felt compelled to see for myself, so I arranged a visit to the New York City Police Department's forensic laboratory, the real-life counterpart of the lab on Law & Order.
The police lab is located in an unglamorous building in the borough of Queens. Much of the work done there is also unglamorous: far more drug cases than homicides. According to Lieutenant Paul Scardino, commanding officer of the lab's controlled substances analysis section, seized drugs from about 200,000 cases are delivered to the lab every year. The contraband ranges from garbage bags full of uprooted marijuana plants to glassine envelopes packed with heroin. Top priority goes to analyzing heroin, cocaine and other felony drugs; to bring an indictment under New York State law, the lab has only five business days to identify a suspected sample and measure its purity, which reveals the weight of the drug. (The severity of the charge depends on the weight.)
Until recently, the lab used color and crystal tests to determine whether a sample contained heroin or cocaine. Investigators would put a few crumbs of powder in five wells on a spot plate, then add a different chemical to each well. The presence of heroin or cocaine would be confirmed by a distinctive set of reactions: the chemicals would change color in some of the wells and form crystals in others. Although this method worked reliably for decades, forensic scientists argued that there was a small chance that an unknown or rare compound could produce exactly the same reactions as the illegal drugs. So over the past five years the police lab has shifted to a high-tech tool more commonly seen in university research facilities: the gas-chromatography mass spectrometer (GCMS).
How does the GCMS work? First, technicians dissolve the drug sample in methanol and place a small amount of the liquid in a vial. The GCMS vaporizes the liquid and uses helium to carry the mix of gases through 15 meters of slender glass tubing coiled inside the machine. Different molecules travel through the tubing at different rates because of interactions with a thin coating on the tube's inside surface. Therefore, the GCMS is able to isolate the heroin and cocaine molecules, which are then bombarded with electrons to ionize them. The ions pass through a magnetic field, and the amount of deflection reveals their molecular weight. If the GCMS fingerprint of a sample matches that of heroin or cocaine, it is nearly impossible for even the best defense lawyer to challenge the result successfully. To ensure the accuracy of the machines, the lab technicians recalibrate each GCMS every morning by testing vials of pure heroin and cocaine obtained from pharmaceutical companies.
The new technology doesn't come cheap: each GCMS costs about $80,000, and the police lab uses two dozen. And because certain drugs-- such as LSD, MDMA (better known as Ecstasy) and ketamine ("Special K")-- are destroyed by high temperatures, the lab also has two liquid-chromatography mass spectrometers that don't require vaporizing the sample. Overall, the controlled substances section employs about 60 people, who are officially called criminalists. Very few conform to the pasty-faced Law & Order stereotype; on the contrary, the staff reflects the extraordinary ethnic diversity of Queens, with a particularly large number of people from India.
Next to drugs, guns are the police lab's biggest commodity. Every year about 10,000 seized guns are sent to the firearms section in the lab's basement. The examiners there first determine whether the guns are operable. (Most firearms used by criminals are not in the best condition.) Then the examiners test-fire the guns to see if the markings imprinted on the shells or bullets match any evidence previously found at crime scenes.
Robert Tamburri, a detective in the firearms section, gave me a vivid demonstration of the test-firing process. He picked up a worn and weathered-looking semiautomatic pistol and took me into a soundproof room. Inside was a large metal tank containing 600 gallons of water. The detectives fire into the tank because water can stop the bullets without damaging the telltale marks made by the gun. I got a bit nervous as Tamburri inserted two nine-millimeter bullets into the pistol's magazine and prepared to fire into the tank's gun port; I'd never been so close to a cocked semiautomatic before. (And I sincerely hope that I never get that close again!) Then the shots rang out--luckily, I was wearing ear protectors--and the shells landed in a net below the gun port. Tamburri opened the tank's lid, and we fished out the two bullets using a suction hose.
We took the shells and bullets to a comparison microscope, which is basically a pair of microscopes joined together so that two objects can be viewed side by side. Looking at both bullets through the stereoscopic eyepiece, I could see that they shared the same pattern of marks left by the rifling (the spiraling grooves inside the gun's barrel that spin the bullet to give it flight stability). But even more striking was the similarity between the marks on the shells: the circular pits made by the firing pin when it struck the shell's primer and the parallel lines imprinted on the shell casing when it recoiled against the breech face. The firearms lab routinely digitizes these images and compares them with the images stored in the Integrated Ballistics Identification System, which archives bullet and shell evidence from crime scenes across the U.S. The software calls up the closest matches; if two images appear to be identical, the examiner retrieves the physical evidence and does a firsthand inspection.
Last but not least, I visited the police lab's trace analysis section, which handles the forensic work most often depicted on TV--examining fibers, paints, papers and other crime scene evidence. This section has enough high-tech instruments to make it the envy of any chemistry department. In one room, investigators use an x-ray diffraction machine to look for crystals in explosive materials; across the hall, they employ a scanning electron microscope to search for the spherical particles present in gunshot residue. Other rooms contain infrared microscopes, an x-ray fluorescence machine and a Raman spectrometer. Tools such as these are indeed used in homicide investigations, but that's just a small fraction of their workload. For example, the lab can find evidence of arson by identifying kerosene or butane in fire debris.
Although some of this work may sound mundane, New York City's police lab is actually more surprising and fascinating than Law & Order's. At one point in my tour of the firearms section, Tamburri led me into a room that contained dozens of old guns, many used for spare parts when investigators need to fix a seized weapon before test-firing it. He picked up a pair of scuffed revolvers that were lying on a desk. One was the gun that Mark David Chapman had used to kill John Lennon in 1980; the other had belonged to David Berkowitz, the "Son of Sam" killer who murdered half a dozen people in the mid-1970s. Staring at the ugly gray weapons, I felt disoriented. My god, I thought. This is a lot stranger than anything I've ever seen on TV.
|drug rehabilitation saving taxpayers|
California taxpayers are saving more money than expected due to ...
|Study: Marijuana Causes Lung Damage|
New research finds that smoking three or four marijuana cigarettes ...
|Thanks to Online Pharmacies, Addiction Can Be Just a Click Away|
WASHINGTON -- Kelly Knable, a 34-year-old mother of three from ...
|Balancing pain and drug addiction|
Over the past two decades, two conflicting medical ideas have ...
|State officials create prescription drug abuse task force|
TALLAHASSEE, Fla. --
State officials on Friday announced the creation ...
|Florida system often fails to catch Medicaid abuse at source|
FORT LAUDERDALE, Fla. - (KRT) - The victim's skin was ...
|Marijuana's rising threat: For more kids, use turns into addiction|
John Brown experimented with marijuana at age 10, and it ...
|Student gets state prison term for selling marijuana|
EASTON -- David Messina had his whole life ahead of ...
|Man charged in cocaine case forfeits $585,000|
An Iowa truck driver arrested by Kentucky Vehicle Enforcement officers ...
|Cocaine Curtails Body's Ability to Cool Off|
In addition to triggering life-threatening cardiovascular episodes, cocaine can be ...
|Science for Cops|
I admit it: I'm a Law & Order fan. ...
|New Gene Therapy Could Help Quell Alcoholic Cravings|
One prevailing view of addiction holds that alcohol and other ...
|One Dose of Cocaine Primes the Brain for Addiction|
It isn't a myth: one dose of cocaine is all ...
|Marijuana Firmly Linked to Infertility|
Scientists from the University of Buffalo have smoked out what ...
|Moderate Alcohol Consumption Clouds Brain's Ability to Detect Mistakes|
It's common knowledge that a brain on booze doesn't function ...