Forensic Evidence – it has its limits and sometimes those limits are your weapon

Posted on January 30, 2025 in Uncategorized

By By Michael J. Nichols

This is a story about Karolyn. Karolyn is a 28-year-old Marine Corps veteran. Karolyn was medically discharged from the "Corps" at 20 years old because a 500-pound bomb fell on her during a training exercise. It did not denotate, but it hurt. It literally concussed her entire body.

Fast forward by about 4 years. A number changes her life again. This number comes from a lab report at a government-operated forensic laboratory. That number is 7. 7 means 7 nanograms (ng) of Tetrahydrocannabinol (THC) per 100 milliliters (mL) of her blood. That number was the difference between Karolyn's status as a victim, who can move on and grieve her dead husband, and Karolyn facing the business end of a prosecution for 2 15-year felonies.

On a surprisingly-snowy late March morning in 2022, Karolyn was driving her husband to work in a small northern-Michigan community. A fast-moving winter squall snuck up on them as they left their house not far from Gaylord. Karolyn's truck hit black ice as she was passing another vehicle. Karolyn lost control. The truck left the road from the passing side to a deep ditch on the left hand side of the road, spun in a freaky way so that Karolyn's husband's head hit the window and he snapped his c-1 (broken neck) and was dead almost instantly.

Karolyn is a medical marijuana patient. She is a medical marijuana patient because she suffered a gruesome injury when that bomb fell on her during an exercise. Even without that legal status for Karolyn, Michigan is a recreational marijuana state and a state where no "presumptive" blood level for marijuana exists. That is important for the lesson in this story.

Dr. Jimmie Valentine of Mississippi was our expert on the disposition of THC (marijuana) in the human body. Dr. Valentine was great at breaking out the polymodal nature of marijuana in distribution and elimination in the human body. The jurors had lots of questions. Geoff. French, a supervisor at the Michigan State Police lab (MSP) in Lansing testified for the prosecutor. The government thought that we would fight them on the accuracy of the THC analysis. A scandal had been recently brought to light, in which non-psychoactive Delta-9 THC isomers (think a sibling of the analyte) were being reported as Delta-9 THC. More on that scandal below:

Dr. Valentine went Wednesday morning and Geoff French went Tuesday night. A great thing about Dr. Valentine is that he was involved in some of the very first studies that had special approval from the United States Attorney General in 1974 that could not correlate marijuana use with impaired driving function.

Geoff French:  throughout some pretrial litigation, I convinced the Judge to hold that French testify ONLY to the lab's procedures. The Prosecutor's concern was that Karolyn's first blood analysis in the spring of 2022 that showed seven nanograms of Delta 9 THC and something along the order of 86 nanograms of the inactive metabolite that was done at the time where the lab's method was literally converting CBD into THC based on the reagent that it was using in the derivatization process.

They then analyzed this blood a second time after they validated the new method with liquid chromatography, mass spectrometry/mass spectrometry. That produced a 7.3 nanogram per milliliter result but interference precluded them from reporting out carboxy or any other analyte. It was around this time that I had the pleasure of getting involved in this case.

Mr. French testified pretrial at a motion hearing as follows: "the presence of THC is proof of use ... it does not prove impairment." Having that testimony in the pretrial motion was such gold. We blew it up on an 11 x 16 foam-board placard to display to the jury on an easel.

I think the prosecutor believed we were going to attack the reliability of the test. I think he also wanted to sneak in testimony about human performance and extrapolation via the lab supervisor and he telegraphed that when he responded to one of our pretrial motions.

I did not ask either of the lab analysts who testified to the first and second report respectively. The whole strategy was "shoulder shrug - hey jury we told you she admitted to using that morning and that she was a medical marijuana patient, who cares about the number."

But when the jurors asked Mr. French questions about things like how long THC stays in the human body and if the tests show how long ago she used, I objected but the Judge let him answer and that opened up the back door for him to sneak in all of his claims about half-life of marijuana and retrograde extrapolation.

I learned a lot about how people feel about marijuana. A lot of people my generation (mid 50's to late 50's) are still not educated in the slightest about marijuana or medical marijuana.

That was fascinating to me. The young jurors were 100% on our side and I was concerned that they would be sheep with the older jurors in deliberations. We had an insurance agent, a teacher, a mechanic, a retired bus driver, but also a medical marijuana patient or former patient who looked like she was in her late 40s. Those were the jobs/careers for the "older" jurors.

Remember, a forensic report or forensic testimony can only provide certain information to a fact-finder. A number in human blood – even if it is demonstrated to be reliable – is only a reflection of what is in someone's system at the time the blood came out of their arm. It is up to the proponent of the theory of the case, i.e. a driver impaired by marijuana who caused a death, to make the connection beyond that. Think about how you can cabin the number to only a meaningless value and not proof beyond a reasonable doubt. Whether that comes via a pretrial motion or a well-crafted argument. A number has limits – use that as a weapon.

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