Trace evidence can be simply described as a small, or tiny, piece of evidence left or taken away from a crime scene. If that definition sounds familiar, it should. In fact, everyone involved in a criminal investigation, including writers of fictional cases, should be aware of Edmond Locard’s Exchange Principle—“every contact leaves a trace.”
In other words, everyone who leaves an area takes something with them. Likewise, everyone who enters a scene deposits something. Now, those “somethings” may very well be microscopic, such as DNA, but something is exchanged by every single person who enters and/or leaves a crime scene.
In the field crime scene technicians and investigators collect every single piece of evidence that could help solve their cases. They bag and tag and transport everything from cars, mattresses, and carpeting, to threads, dandruff, and chips of paint.
However, until those pieces of evidence are tested and confirmed by a laboratory scientist or technician, they are nothing more than inanimate objects without substantial meaning or purpose.
It is the laboratory scientist/examiner who adds the icing to the investigator’s cake by attaching a certified and positive identification and, an official quantity to the unidentified and/or unnamed evidence. In short, it’s not blood until the lab says it’s blood.
So, what does it take to be a forensic laboratory examiner? (I’ll be referencing the Commonwealth of Virgina. Things could very well be different in your area).
1. New trainee examiners within the Division of Forensic Sciences’ Trace Evidence Section, begin their training in only two specific areas, from a list of several—Explosives, Fire Debris, Glass, Hairs and Fibers, and Paint, or Primer Residue.
2. Trainees are closely supervised by an experienced trainer. The supervisor/trainer assigns the newcomer a training schedule, which includes studying the department training manual and completing a summary form as each section is completed.
3. The training period for a new trainee is approximately 12 months. Both oral and written quizzes take place throughout the duration of training. Testing regarding the use and knowledge of laboratory instruments is conducted by the chemistry manager, who issues either a pass or fail grade. All of this takes place while the trainee learns and works side-by-side with, and under the watchful eye of their trainer.
4. Trainees are required to maintain a notebook containing all training summaries and required reading as assigned by the trainer.
5. Trainees are required to read, study, and become familiar with instrument manuals provided by the manufacturer(s).
6. At the completion of the training program, each trainee must successfully complete an oral competency exam. The exam must be completed within 3 hours.
7. A second part of the final exam is a practical test, where the trainee demonstrates his/her ability to work a mock case and then present their findings in a moot court, complete with a “prosecutor, judge, and defense attorneys.”
8. Once the training program is complete the Chemistry Manager recommends that the trainee be certified. It is also time for the trainee to submit a buccal swab for DNA testing. The result is stored in the staff DNA database for comparison and elimination in the event evidence contamination comes into question.
9. Required reading is an ongoing process for trainees. Included in their lengthy reading list are:
Handbook of Forensic Services, FBI Laboratory
Moenssens, Andre A., et. al., Scientific Evidence in Criminal Cases, 3rd Ed., The Foundation Press, Mineola, NY, 1986, pp. 1-74.
10. Trace Evidence Section trainees must be familiar with the Federal Rules of Evidence.
11. Trainees must thoroughly understand the admissibility of scientific tests to include the difference between “Frye” and “Daubert.”
12. A vital part of the duties of a trace evidence examiner is the courtroom testimony regarding their findings. And, to sharpen those skills they’re required to read more page-turners, such as:
Burke, J. L., “Testifying in Court,” The Legal Digest, September 1975, pp. 8 – 13.
Hodge, E. and Blackburn, B. “Courtroom Demeanor,” AFTE Journal, pp. 7–14
Finally, it’s time for the trainee to…
…begin his/her first case, solo. Their next hurdle could/would be to tackle two new areas of trace evidence examination. To do so, they’d begin an abbreviated version of this process again, and would continue to do so until they’d mastered each category of trace evidence.
After all, who wouldn’t want to expand their horizons in 5 or 10 years by moving from examining bits of dandruff all the way up the ladder to analyzing tiny flakes of dried paint? The pace must be exhilarating.
My heart is pounding just thinking about it.
Operating a motor vehicle is privilege granted to you by your home state. When applying for, and signing a drivers license, you agree to comply with a law enforcement officer’s request to submit to a breath or blood test, and possibly a urine test. The law governing this agreement is called the Implied Consent Law. Each state has some form of the law and, whichever state you happen to drive through, you are subject to their motor vehicle laws. In other words, what may be legal in your home state may or may not be legal in another. You are, however, responsible for complying with the laws of each.
For the purpose of this article I’ll refer to the laws and procedures in the Commonwealth of Virginia, for that is where I was a police officer and licensed breathalyzer operator.
When pulled over by a police officer you are required to do a few things upon request by the officer—provide a valid drivers license, proof of insurance, and you must submit to a breath or blood test, or both, if arrested for suspicion of driving while under the influence of alcohol and/or drugs. A refusal to do so may result in the suspension of your drivers license and other penalties.
Let’s skip a few steps and say the accused has submitted to the blood test and now that blood sample has been delivered to the lab for testing. The arresting officer requested tests for the presence of drugs. She also stated that preliminary breath tests indicated the absence of alcohol, yet, the driver’s actions strongly pointed to the influence of “something.”
In Virginia, the Department of Forensic Science (DFS) provides all DUI/DUID Blood Specimen Collection Kits. This kit contains two gray top blood vials, two Certificates of Blood Withdrawal, povidone iodine swab to cleanse the suspect’s arm, and evidence seals.
Only the following may draw the blood sample(s): a physician, registered nurse, licensed practical nurse, phlebotomist, graduate laboratory technician or a technician or nurse designated by order of a circuit court acting upon the recommendation of a licensed physician. Police officers DO NOT collect blood samples.
Vials are sealed and placed in a container provided by DFS. They are then mailed or hand delivered by the officer to the DFS.
At the DFS laboratory, scientists screen the blood sample for a standard panel of drugs (unless the officer indicates the possibility/suspicion of a specific drug based on investigation—she found a labeled pill bottle, etc.).
When possible, officers should be specific when requesting lab testing. For example, if the officer has reason to suspect the offender has consumed specific drugs, the description on the lab request form might read—Item 1. One DUI kit containing two vials of suspect’s blood: Toxicology – test for cocaine and marijuana.
If the drug is unknown, only the following are included in the initial drug screen panel.
If a drug is detected during the screen, the scientist’s report will include the drug name and the quantity found in the blood. The report will also list the drugs NOT found in the blood. For example:
Oxycodone 0.12 mg/L.
The following substances were not detected:
Blood samples are sometimes collected in non-motor vehicle-related cases, such as child endangerment, manslaughter, drug-facilitated sexual assault, and possession/ingestion of illegal drugs (suspect swallows unknown but suspected drugs).
Sexual assault cases involving the drugging of the victim require the assistance of Sexual Assault Nurse Examiner (SANE) who will collect two blood samples and a urine sample from the victim, if the rape occurred less than 24 hours prior to examination. If the rape occurred more than 24 hours prior to examination, the SANE nurse will collect a urine sample only. These samples are kept separate from the Physical Evidence Recovery Kit (PERK Kit, which is sometimes and unofficially referred to as a “rape kit”).
Suspected poisoning cases are handled differently and require special handling and evidence collection procedures. This, my friends, is a topic for another day.
*Remember these procedures and testings apply to the Commonwealth of Virginia. They may vary in other states. But they are a good rule of thumb for fiction, or, if your story is set in Virginia, reality.
*DUID is an acronym for Driving Under The Influence of Drugs
Countdown to the WPA
The Writers’ Police Academy
Get to Know Lee Lofland
Lee Lofland is a nationally acclaimed expert on police procedure and crime-scene investigation, and is a popular conference, workshop, and motivational speaker.
Lee has consulted for many bestselling authors, television and film writers, and for online magazines. Lee has appeared as an expert on national television, BBC Television, and radio shows.
Lee is the host and founder of the Writers’ Police Academy, an exciting, one-of-a-kind, hands-on event where writers, readers, and fans learn and train at an actual police academy.
To schedule Lee for your event, contact him at firstname.lastname@example.org.