Law Enforcement Expert Witness Testimony on Marijuana Odor Rejected

Law Enforcement Expert Witness Testimony on Marijuana Odor Rejected

On July 1, 2020, Officer Jack Gilboy (“Gilboy”) of the St. Charles Parish Sheriff’s Office approached Plaintiff Cedric Otkins (“Otkins”) while Otkins was sitting alone in his parked car at the East Bank Bridge Park in St. Charles Parish, Louisiana. Otkins filed this civil rights action alleging a violation of his Fourth Amendment right to be free from unreasonable search and seizure.

Officer Gilboy claimed that he smelled marijuana emanating from Otkins’ vehicle after Otkins exited his vehicle.

Plaintiff sought to exclude the Defendant’s expert witness, Craig Wiles, from testifying at trial. In his expert report, Wiles opined that under the circumstances of the traffic stop on July 1, 2020, Gilboy could smell marijuana odors emanating from the interior of Plaintiff’s vehicle.

Law Enforcement Expert Witness

Craig M. Wiles is a career law enforcement officer and narcotics agent with over forty years of experience. He joined the Drug Enforcement Administration as a special agent in 1995. He has been a part of several such investigations which have resulted in hundreds of arrests for drug violations, including marijuana possession and trafficking.

Discussion by the Court

Wiles is a career law enforcement officer and narcotics agent retained to opine on Defendant Gilboy’s ability to detect the odor of marijuana.

The Court Cannot Test Wiles’ Determination of Whether Gilboy Smelled Marijuana

In Wiles’ expert report, he opined that marijuana had an unmistakable odor that “became part of the user’s life” and that Gilboy “could smell the odor of marijuana coming from the interior of Otkins’ vehicle.” Because this opinion was not based on any reliable principles or methods and did not assist the trier of fact, the Court excluded Wiles from testifying at trial in this matter.

Moreover, Wiles’ purported expertise stemmed from his years working in law enforcement as a narcotics agent. Plaintiff questioned the Defendant’s statement claiming that Wiles was an expert in olfactory science despite not being proffered as such by the Defendant. Plaintiff argued that even if Wiles relied upon his own experience in law enforcement, the Defendant still had to demonstrate that Wiles applied a methodology that was reliable, verifiable, and generally accepted in the relevant community. Instead, Defendant claimed that Wiles was not rendering a “scientific expert opinion” but an opinion based on his specialized knowledge and expertise.

The Court held that Defendant failed to show that Wiles is an expert in the olfactory sciences or in the human ability to detect certain odors.

Wiles’ expert report lacks any discernable methodology or principle

Wiles’ opinions were based on what he deemed a “vacuum effect” caused by the opening and closing of Plaintiff’s car door, allegedly pushing the odors toward Gilboy, as well as the weather conditions at the time of the stop, which allegedly helped to enhance the smell. He provided no support for either of these opinions other than a general invocation of his years of experience. Wiles also relied on and quoted at length a blog post from a hydroponics company regarding the smell of cannabis plants without considering how the odor of cannabis plants, the subject of the article, might differ from the odor of marijuana fit for consumption.

Wiles’ opinions were not helpful to the trier of fact

Although couched as expert opinion based on years of experience, much of Wiles’ report mainly consisted of commonsense conclusions that did not require expert testimony.

For example, Wiles’ opinion that marijuana has a distinct and strong odor is not an expert opinion. Indeed, as Wiles recognizes in his report, “all who visit” New Orleans can receive “an education on the smells of marijuana” whether through “[a] drive on the Interstate through the City, a walk through the streets or a day shopping in a grocery store,” underscoring that his opinions are based on common sense and practical experiences within the realm of the average juror. Further, his opinions that the odor of marijuana can remain trapped on the clothing and skin of a user and in a user’s vehicle was likewise a common sense opinion that did not require expert testimony, especially where, as here, Wiles provided no evidence or sources to support his claims or to provide greater detail.

Wiles’ opinions that the closing of Plaintiff’s car door could have fanned marijuana odors toward Gilboy and that “the environmental conditions of a light to mild wind at night in a secluded area, under a bridge in the Park would enhance the smells for two people at a distance of 3–15 feet” were similarly unhelpful to the jury. It followed that this opinion was within the common sense of the jury as well. Likewise, Wiles’ opinion about the wind blowing and enhancing any odors required no expertise and thus was unhelpful to the jury.

The Court held that they were essentially lay opinions that do not require any expertise to reach.


The Court excluded the testimony of Defendant’s expert witness, Craig Wiles. It has not arrived on an outcome for this case since the remaining issues involved in this case still await resolution.

Key Takeaways:

  1. Lack of Demonstrated Expertise: The court scrutinized the qualifications of the expert, highlighting the necessity for a demonstration of expertise in the relevant field. In this case, Wiles’ background as a law enforcement officer did not inherently qualify him as an expert in olfactory science.
  2. Absence of Reliable Methodology: Wiles’ expert report lacked a discernible methodology or principle, with opinions often based on subjective observations rather than verifiable principles. This underscored the importance of experts employing reliable and verifiable methodologies in their analyses.
  3. Commonsense Conclusions vs. Expert Opinions: The Court distinguished between commonsense conclusions and expert opinions, emphasizing that expert testimony should offer insights beyond what an average juror could discern. The Court deemed Wiles’ opinions, such as the distinct odor of marijuana, common knowledge rather than expert analysis.
  4. Limited Utility to the Trier of Fact: The Court deemed many of Wiles’ opinions unhelpful to the trier of fact, as they either echoed common knowledge or were based on subjective assessments that did not require specialized expertise. The Court emphasized the need for expert testimony to provide insights beyond lay understanding.

Case Details:

Case Caption:Otkins V. Gilboy Et Al
Docket Number:2:21cv1275
Court:United States District Court, Louisiana Eastern
Citation:2024 U.S. Dist. LEXIS 44958
Order Date:March 14, 2024


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