Section 4.4: Drug & Chemical Evidence

Fundamentals of Criminal Investigation by Adam J. McKee

Forensic chemistry stands out as one of the most varied areas in forensic science. Experts in this field, known as forensic chemists, handle a wide array of evidence types, including those we’ve touched on before like paints and soils. In this section, our spotlight turns to the examination of drugs and gunshot residue, showcasing the critical role these substances play in criminal investigations.

Analyzing Drug Evidence

Initial Examination

In the bustling environment of the crime lab’s chemistry section, scientists embark on the meticulous task of analyzing evidence for illegal substances. This evidence varies widely, from plant materials like marijuana to synthetic drugs, liquids from drug production sites, and various drug paraphernalia.

Preliminary Testing

The journey begins with an initial examination, where the evidence’s packaging is inspected for tampering and a visual assessment is conducted. Measurements such as weight, volume, or unit count are taken. Following this, chemists conduct preliminary tests using chemical reactions to get early indications of the substance’s identity.

Confirmation and Reporting

Further testing involves sophisticated techniques to confirm the presence of controlled substances. The culmination of this process is a comprehensive report detailing the amount and types of drugs identified. In certain cases, the lab also determines the drug’s purity, especially if required by law enforcement or legal proceedings.

Courtroom Testimony and Expertise

Forensic chemists play a crucial role beyond the lab, often providing expert testimony in court. Their expertise not only aids in legal decisions but also serves as a resource for controlled substance information, supporting the broader goals of criminal justice and public safety.

🔍 Reflect

How does the process of analyzing drug evidence support the broader goals of criminal justice and public safety?

National Forensic Laboratory Information System (NFLIS)

The National Forensic Laboratory Information System (NFLIS) continues to play a pivotal role in providing critical insights into the nation’s drug problems by collecting and analyzing drug identification results from drug cases submitted to federal, state, and local forensic laboratories. Established in 1997 by the Drug Enforcement Administration (DEA), NFLIS has evolved to include various components, such as NFLIS-Drug, NFLIS-TOX, and NFLIS-MEC, each contributing unique data to enhance understanding and response to drug trends.

The 2022 NFLIS-Drug Annual Report revealed that state and local forensic laboratories in the U.S. identified a total of 1,181,750 drug reports, highlighting the ongoing challenges and shifts in drug use and trafficking patterns. Among these, methamphetamine was the most frequently reported substance, followed by cocaine, fentanyl, cannabis/THC, and heroin. These findings underscore the importance of NFLIS in supporting drug scheduling decisions, informing drug policy, and guiding enforcement initiatives both nationally and locally​ (NFLIS)​​.

Reflecting on the broader impact, the NFLIS data not only informs about the prevalence of specific drugs but also offers a deeper understanding of regional drug trends. For instance, methamphetamine remains highly reported in certain regions, whereas other areas may see higher reports of fentanyl or heroin. Such detailed regional insights are critical for tailoring public health responses and enforcement strategies to the unique challenges faced by different communities across the country.

Furthermore, the inclusion of new substances in NFLIS reports, such as synthetic cannabinoids and emerging opioids like fluorofentanyl, highlights the adaptability of the system to evolving drug trends. This adaptability is crucial for early detection of emerging drug threats and facilitates a proactive rather than reactive approach to drug policy and enforcement​ (NFLIS).

In summary, the ongoing work of NFLIS and the insights provided by its comprehensive reports are invaluable resources for understanding and combating the complex landscape of drug use and trafficking in the United States.

Drug Categories

This section breaks down the world of illegal drugs into different groups based on their effects. Understanding these categories is crucial for investigators. It’s like having a cheat sheet at a crime scene – knowing the drug type helps them identify what they’re dealing with, just like a mechanic uses specific tools for different car problems.

Painkillers Gone Wrong: Narcotic Analgesics

First up are narcotic analgesics. These are powerful prescription pain relievers, like hydrocodone and oxycodone. Unfortunately, some people misuse them to get high. Studies show a significant number of people have misused these medications in the past, and it’s a trend investigators need to be aware of, especially when dealing with younger adults.

Chill Pills and Party Drugs

Next, we have two categories: benzodiazepines and club drugs. Benzodiazepines are medications prescribed to calm people down or help them sleep, like Xanax. Sometimes, young people misuse these to get high as well.

Club drugs, on the other hand, are illegal substances like MDMA (Ecstasy), ketamine, and GHB, often used at parties or raves. MDMA use has fluctuated over the years, so staying updated on current trends is important. Investigators need to be aware of these drugs because they can be dangerous and lead to serious health problems.

Building Bigger Muscles (Illegally): Anabolic Steroids

Anabolic steroids are hormones that can help people build muscle faster. While some doctors prescribe them for medical reasons, many people get them illegally. There have been fluctuations in steroid use, but it’s important to be aware of their presence in gyms or fitness centers suspected of illegal activity.

Speeding Things Up: Stimulants

Stimulants are drugs that give people a burst of energy. Methamphetamine is a highly addictive stimulant that remains a major problem. Law enforcement continues to battle illegal meth labs. Investigators need to be able to recognize signs of meth use at crime scenes.

Mixing and Matching: Dangerous Drug Combinations

Taking multiple drugs at once, even if they seem harmless on their own, can be deadly. Cocaine and heroin (often called a “speedball”) is a particularly risky combination. Investigators need to be aware of these dangerous mixes so they can take proper precautions when handling drug evidence.

Cocaine and Heroin: A Deeper Look

Cocaine and heroin are two of the most dangerous illegal drugs. These drugs are often mixed with other substances, either to make them stronger or cheaper. Investigators need to be familiar with these different combinations to understand what they’re dealing with at a crime scene.

Remember: This is just a glimpse into some common illegal drug categories. As a criminal investigator, you’ll need to stay up-to-date on the latest information about the specific effects and dangers of each type of drug.

🔍 Reflect

Why do you think it’s important for criminal investigators to understand different drug categories?

Hair Toxicology

Hair analysis has emerged as a significant forensic tool for detecting past drug use. This technique offers a unique window into an individual’s drug history through segmental analysis, which involves examining hair strands in sections to identify and measure drug concentrations along the hair shaft. Hair analysis proves particularly valuable when compared to traditional methods like urine or blood testing due to its capacity to detect not only recent use but also longer-term patterns.

Advantages of Hair Analysis

The core advantage of hair analysis lies in its non-invasive nature. Sample collection is straightforward and painless, making it suitable for various applications such as workplace drug testing or court-mandated treatment programs. Additionally, hair’s continuous growth offers the potential for retesting if initial results are inconclusive or contested.

Hair analysis surpasses traditional methods in several key ways. Unlike urine samples, which provide only a short-term detection window, hair offers a much broader timeframe for identifying past drug use. Hair growth, averaging one centimeter per month, essentially creates a historical record of drug use along the hair shaft. This proves invaluable in situations where traditional biological samples are unavailable, such as decomposed bodies, or when establishing a complete drug history is paramount. For instance, hair analysis can be instrumental in investigating drug-facilitated sexual assaults where the time frame of the incident is crucial.

Furthermore, hair analysis serves as a valuable tool for monitoring drug compliance and abstinence programs. Its extended detection window allows for a more comprehensive assessment of an individual’s adherence to treatment protocols. The increasing popularity of hair analysis stems from its ability to provide a more comprehensive picture of drug use compared to urinalysis, which offers a limited window of detection.

Limitations to Consider

It is essential to acknowledge a potential limitation associated with hair analysis. Certain cosmetic hair treatments can degrade drugs trapped within the hair shaft, potentially impacting the test’s accuracy. Investigators must consider an individual’s hair history when interpreting test results.

In conclusion, hair analysis stands as a powerful tool within the investigator’s arsenal. It offers a unique and non-invasive method for detecting past drug use, providing a valuable historical record along the hair shaft. While some limitations exist, hair analysis remains a critical tool for investigators seeking a more comprehensive understanding of an individual’s drug use.

Gunshot Residue

Gunshot residue (GSR) refers to microscopic particles expelled during the discharge of a firearm. These particles can be transferred to the hands, clothing, or surrounding environment, and their presence can be a crucial piece of evidence in firearm-related investigations. Effective GSR collection requires meticulous procedures to ensure the integrity and admissibility of the evidence.

Preparation is Key

Investigators should arrive at the scene equipped with a GSR collection kit, paper envelopes, paper towels, clean paper for documentation, a waterproof pen for labeling, evidence tape for sealing containers, powder-free gloves to maintain chain of custody, and face protection as a safety precaution.

Identifying Subjects for Testing

The decision to test individuals for GSR presence depends on the specific circumstances of the case. For instance, suspects who may have fired a weapon, victims potentially exposed to gunfire, or witnesses in close proximity to the shooting might all be considered for GSR collection.

Timely Collection is Paramount

The success of GSR analysis hinges on collecting samples as soon as possible after the incident. Ideally, investigators should collect GSR from the hands of relevant individuals immediately. However, if immediate collection isn’t feasible, investigators should individually bag the subjects’ hands in paper bags, not plastic, to prevent sweating which can diminish GSR particles. Modern GSR collection kits typically employ swabs or discs designed for collecting samples from the webbing between the fingers, an area where GSR particles are often concentrated. It’s crucial to follow the specific instructions provided with the GSR kit being used to ensure proper sample collection.

Preserving the Evidence

Investigators must take steps to safeguard the collected GSR evidence. Individuals who might have GSR on their hands should be instructed to refrain from washing their hands or using any liquids on them. They should also avoid rubbing their hands on clothing, furniture, or other surfaces, as this can transfer or remove GSR particles. Furthermore, GSR collection kits should be kept separate from firearm evidence to prevent any potential contamination.

Extending the Reach of GSR Collection

The procedures outlined for hand collection can also be applied to collect GSR from vehicles or other surfaces that may have been exposed to gunfire. By adhering to these meticulous collection techniques, investigators can effectively gather this vital evidence for forensic analysis, ultimately aiding in a comprehensive investigation.

References and Further Reading

Modification History

File Created:  05/02/2019

Last Modified:  04/05/2024

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