Expert countertestimony is often needed by criminal defendants at trial

Expert countertestimony (EC) is often vital for a criminal defendants’ trial, as is made clear with recent unpublished Virginia Court of Appeals affirmance of a DUI (driving under the influence of alcohol and drugs) conviction that ideally called not only for EC but also an emphasis on the Virginia law’s non-presumption of driving under the influence of alcohol for blood alcohol concentration (BAC) test results  below 0.08. Virginia Code § 18.2-269. Although Virginia prosecutors / assistant commonwealth attorneys should not be expected to automatically present expert testimony (ET) for every DUI case with a BAC reading, that should be more often expected when DWI with death or severe resulting injury is alleged, and certainly when the BAC is determined by a blood draw, which precludes the factfinder (whether the judge at a bench trial, or a jury) from knowing the BAC reading absent the testimony of a blood analyst, unless the prosecution has timely and correctly filed a notice of intention to introduce the BAC result with no timely and correctly filed objection from the criminal defendant.

Expert countertestimony can be needed all the more when the Virginia criminal defendant has blabbed to the police about their culpability

Jason Alexander Wallace fatally struck a pedestrian and drove home, thus adding a hit and run charge to the Virginia criminal counts prosecuted against him. “Wallace told Officer Holmes that he ‘took three to five … bumps’ of cocaine, ‘smoked half a blunt of marijuana,’ and ‘drank four shots of tequila’ between 6:00 and 9:00 p.m., before the 10:30 p.m. incident.” Wallace v. Commonwealth of Virginia, Record No. 1403-24-2, 2025 WL 3150997 (Va. App.) (unpublished). Even if,  Wallace’s lawyer did everything that was needed to have been done to defend him (other than apparently not presenting expert countertestimony at trial), clearly an essential point of defense here was to pursue whether it could have been argued that Wallace made those damning admissions to police against his Fifth Amendment or Miranda rights. Nonetheless, his foregoing damning admissions did come into evidence at his non-jury trial. Wallace’s admissions were further damningly combined by the prosecutor with the Virginia Department of Forensic Science (DFS) certificate of analysis (COA) — as testified by DFS forensic toxicologist Jane Thatcher that Dr. Jane Thatcher — that Dr. Thatcher “examined Wallace’s blood sample. Drawn at 2:55 a.m., Wallace’s blood contained a blood alcohol concentration (BAC) of 0.054, a cocaine concentration of 0.011 milligram per liter, a benzoylecgonine concentration of 0.13 milligram per liter, a tetrahydrocannabinol (THC) concentration of 0.0010 milligram per liter, and a THC carboxylic acid concentration of 0.010 milligram per liter.” Wallace. With Wallace’s presenting no EC, DFS toxicologist Thatcher’s following damning testimony was presented.

A Virginia criminal defendant does not automatically need expert countertestimony to object to prosecution witness testimony flying in the face of Virginia law creating no presumption of adverse influence from a BAC under 0.08

The prosecution in Wallace’s case, presented testimony — without expert countertestimony — from Dr. Thatcher that flew in the face of Virginia law creating no presumption of adverse influence from a BAC under 0.08. Wallace tells us that Dr. Thacher testified to a 0.054 alcohol BAC in Wallace’s blood. The certificate of analysis would also have stated a measurement of uncertainty of plus/minus a number in the 0.001-0.009 range. On top of that, whether or not that was done with Wallace, his lawyer had the opportunity to have obtained a court order within ninety days of the incident date for a sample of his drawn blood to have been sent to a private lab for analysis. The private lab where I usually have such blood samples sent regularly reaches a BAC reading lower than that of the DFS. In any event, Virginia law presents the following rebuttable presumptions about BAC under 0.08: “If there was at that time [of breath analysis or blood draw] 0.05 percent or less by weight by volume of alcohol in the accused’s blood or 0.05 grams or less per 210 liters of the accused’s breath, it shall be presumed that the accused was not under the influence of alcohol intoxicants at the time of the alleged offense; 2. If there was at that time in excess of 0.05 percent but less than 0.08 percent by weight by volume of alcohol in the accused’s blood or 0.05 grams but less than 0.08 grams per 210 liters of the accused’s breath, such facts shall not give rise to any presumption that the accused was or was not under the influence of alcohol intoxicants at the time of the alleged offense, but such facts may be considered with other competent evidence in determining the guilt or innocence of the accused.” Virginia Code § 18.2-269. Expert countertestimony could have helped Wallace at trial.

Get your blood sample sent to a private lab for analysis, if charged with Virginia DUI based on a blood draw

Had Wallace obtained an analysis of his blood by a private lab (and possibly he did, as the court opinion in his case does not show all defensive actions taken by Wallace) showing a BAC under 0.05 (a BAC under 0.05 statutorily presumes not being under the influence of alcohol, as explained above) (whether using the measurement of uncertainty or not), he could have timely and correctly filed that private lab analysis with the court pursuant to Virginia Code § 19.2-187  to have made that private certificate of analysis admissible in evidence (and also instead or in addition could have presented expert countertestimony of the private lab analyst), but left unknown here is whether such a private certificate of analysis was or would have been favorable to Wallace. On top of that, the downside of the defendant’s filing such a certificate of analysis is that such a filing can constitute an evidentiary admission by the defense. 

Object to retrograde extrapolation testimony

Wallace’s trial judge heard testimony from the DFS blood analyst Dr. Thatcher about retrograde extrapolation: “Thatcher explained retrograde extrapolation, a calculation used to estimate a person’s BAC at an earlier time, assuming the person’s body has absorbed all the alcohol ingested and is purely eliminating it. Applying retrograde extrapolation to the blood evidence in Wallace’s case, Dr. Thatcher opined that Wallace’s BAC was likely 0.09 percent to 0.13 percent by weight by volume when he struck the victim with his vehicle.” Wallace. That testimony was highly objectionable and could have benefitted expert countertestimony on behalf of Wallace, to explain that the evidence is insufficient to show that his BAC was lower (versus higher) at the time of driving than at the time of his blood draw, in that first alcohol absorbs into the bloodstream (causing a rising BAC), the BAC next plateaus and the BAC next dissipates. Wallace admitted to four shots of tequila less that two hours before the accident. Had those shots been consumed closer to the two hours before the collision, his BAC may all the more still have been rising at the time that his blood was drawn. On top of that, it seems that Dr. Thatcher was without the following information to have known whether Wallace’s BAC was higher at the time of driving than at the time of his blood draw: Wallace’s eating behavior before the collision (eating can slow the absorption of alcohol into the blood stream, and can increase the chance that the BAC is higher at the time of a blood draw than at the time of driving); Wallace’s metabolic activity; and Wallace’s body weight (not as listed on his driver’s license, but his actual body weight).

Fully confront claims of adverse effects of combining intoxicants

Wallace’s prosecutor had a field day with Dr. Thatcher’s testimony — without expert countertestimony — about the possible effects on Wallace’s driving from his ingested intoxicants and the combination of all three: “Dr. Thatcher opined that cocaine causes increased risk-taking behaviors, affects the quality of decision-making, and compromises vision. She added that THC affects balance, coordination, perception, and reaction times. Dr. Thatcher explained that the combination of alcohol, cocaine, and THC could increase their effects.” Although Wallace admitted to three to five “bumps” or snorts of cocaine, he apparently did not disclose the weight or volume of each snort. Certainly, it bore bringing to the judge’s attention that the 0.011 mg per liter of cocaine found in his blood was nearly half the 0.02 milligrams of cocaine per liter of blood threshold at the time of driving to constitute per se guilt under Virginia Code § 18.2-266(v)(a). Although Wallace admitted to having smoked half a blunt of marijuana, it does not appear that the DFS toxicologist knew the weight or volume of the marijuana that was smoked. THC can take weeks to eliminate from the bloodstream, so the THC level in Wallace’s bloodstream by itself did not correlate with impaired driving. 

Exercise your right to remain silent with the police

Had Wallace simply remained silent — as was his right at all times under the Constitution’s Fifth Amendment — with police, his lawyer would have been able to argue more than with his admission, to no correlation between the THC level in his blood and impairment. A similar argument may have been available to limited (if any) correlation between the cocaine level found in his blood and impairment. At all times, Wallace’s lawyer had available the statutory presumption of no guilt merely from a BAC under 0.08 for alcohol.

Fairfax criminal lawyer Jonathan Katz knows how critical it is to obtain the necessary evidence and conduct the necessary investigation in your case, and to review the applicable evidence and law with a fine-toothed comb. Jon Katz relentlessly pursues your best defense against Virginia felony, misdemeanor and DUI prosecutions. With your initial free in-person confidential consultation with Jon Katz, you will feel more confident and well-informed about your essential case defenses. Usually Jon can offer to meet with you within a day of your contacting us at 703-383-1100, Info@KatzJustice.com or (text) 571-406-7268.