Hannah Knowles - Direct/Cross

MS. KNOWLES: Yes, I do.

MS. KNOWLES: Good afternoon.

MS. KNOWLES: Certainly. My name is Hannah Knowles. My last name is spelled K-N-O-W-L-E-S.

MS. KNOWLES: I'm a forensic scientist at the Massachusetts State Police Crime Lab.

MS. KNOWLES: I have a bachelor of science from Simmons University in Boston, and — I'm sorry — a master's of science in forensic science from the George Washington University.

MS. KNOWLES: Since October of 2006.

MS. KNOWLES: I'm currently a forensic scientist 4 in the toxicology unit.

MS. KNOWLES: I was initially hired as a chemist 1 in the drug identification or narcotics unit. After about a year in that position, I was promoted to a chemist 2 position. After about a year, there was a position available in the toxicology unit. So I applied for that available position. Transferred to the tox unit in about August of 2007. And I've been in the toxicology unit ever since.

MS. KNOWLES: At the time the job series for folks that worked at the crime lab was the chemist series. A chemist 1 was an entry level or trainee type position where the individual was responsible for progressing through the training program and assisting with casework as they are authorized on different modules. A chemist 2 was a bench level analyst — someone who had completed training or had a significant amount of authorizations and could work on casework and worked independently from that point forward.

MS. KNOWLES: The chemist 3 series that was in place prior to 2014 was a first level supervisory role. It was somebody who oversaw the day-to-day operations and the work of forensic scientists 1 and 2, or chemists 1 and 2. And

MS. KNOWLES: In 2014, those chemist classifications that I was describing got changed to forensic scientists. Forensic scientists 1, 2, 3, 4, and 5 is the series. Currently, I'm a forensic scientist 4. And so my role is overseeing training and validation for the toxicology unit.

MS. KNOWLES: Yes, there is.

MS. KNOWLES: As part of our accreditation, analysts are required to participate in continuing education at least once per year as they continue to work in their role. Continuing education can consist of participating in workshops or webinars, attending conferences or meetings, or documenting ongoing literature review of new journal articles as they're published.

MS. KNOWLES: Proficiency testing is something that we utilize in the laboratory to assess processes and competencies of an individual as well as the processes that are in place for a particular unit or department or scope of testing. Proficiency testing is also an accreditation requirement. Individuals are required by our internal processes to participate in proficiency testing at least once per year as sort of an ongoing assessment. And what a proficiency test is, is materials that are purchased by the laboratory from a third-party vendor. Those materials are analyzed as if they were casework, but there are expected results or known results for those samples.

MS. KNOWLES: Once the laboratory processes those samples, just like their casework, we submit the results to the external vendor that we purchase the materials from, the results are compared to the expected results, and we have to have our results meet those expected results in order for the proficiency test to be considered successful.

MS. KNOWLES: Yes, I have.

MS. KNOWLES: To the best of my knowledge, yes.

MS. KNOWLES: Yes, it is.

MS. KNOWLES: The Massachusetts State Police Crime Lab is currently accredited by the American National Standards Institute, National Accreditation Board.

MS. KNOWLES: The accreditation process consists of on-site assessments as well as remote or virtual assessments to evaluate our policies and procedures, our personnel, our management, as well as our facilities, to ensure that we are meeting established accreditation standards. The standards that we're currently accredited to is an international standard — 17025 — with additional requirements for forensic testing laboratories. And so there are folks that come from that organization, ANAB, that come to evaluate all of those different aspects of our processes to ensure that we are meeting the standards set out in their requirements.

MS. KNOWLES: Yes, we're currently accredited to that standard.

MS. KNOWLES: Forensic science generally is the application of science to questions of law.

MS. KNOWLES: Toxicology generally is the study of chemicals and other substances and how they impact a living organism or a person.

MS. KNOWLES: Forensic toxicology is generally looking at drugs and alcohol in the human body and how it affects the individual, and applying chemistry and other disciplines to measure the concentration or determine the presence or absence of relevant substances.

MS. KNOWLES: Yes, there are.

MS. KNOWLES: Generally, alcohols are a family or a group of drugs or chemicals that have a specific functional group or a specific structure. The types of alcohols that are analyzed in the laboratory that I work include methanol, ethanol, and isopropanol.

MS. KNOWLES: They all have similar but slightly different structures. Methanol is a solvent. Sometimes it's called wood grain alcohol. Isopropanol is rubbing alcohol — or 2-propanol. And that is typically used as a disinfectant. And ethanol is the type of alcohol that we typically are referring to when we talk about alcoholic beverages. It's what's present in those types of liquids.

MS. KNOWLES: Yes, I am.

MS. KNOWLES: Sure. A central nervous system depressant is a drug or a substance that works to slow down the reactions of nerves in your body. It makes nerve cells slower or less likely to respond to stimulus.

MS. KNOWLES: Yes, it is.

MS. KNOWLES: The effects depend on the concentration or the amount that's present in the body. Effects range, depending on that concentration, from slowing reaction time, reducing heart rate or respiration rate in an individual. That slower respiration rate can also result in drowsiness or unconsciousness. Slower reaction time and more limited muscle control can also result in outward appearances like a staggering gait or slurred speech. It can impair balance and motor coordination, because nerves are responding more slowly. Ethanol specifically can also impact your brain's ability to form new memories. It can impact your body's ability to perceive and apply critical thinking.

MS. KNOWLES: Again, all of those effects that I just described — they can be present depending on the concentration and the individual and how they're responding to that particular concentration of ethanol at any particular time.

MS. KNOWLES: Generally, supervisors will come up with a monthly schedule or rotation where the different types of work in the unit are divided amongst authorized analysts. And then casework is assigned according to that rotation. If an individual has previously been assigned work for that case or has previously issued a report for that case, then sometimes we go off rotation and assign a case according to that previous involvement or previous report that was issued for the case.

MS. KNOWLES: Yes, I was.

MS. KNOWLES: I was asked to prepare a serum conversion report and a retrograde extrapolation report relative to this case.

MS. KNOWLES: I've prepared over a hundred serum conversion reports since I was authorized in 2008.

MS. KNOWLES: I would say approximately 15.

MS. KNOWLES: Certainly. A serum conversion is a service that the laboratory offers when a blood ethanol or a serum ethanol concentration has been determined and it would be helpful or relevant for us to approximate what a corresponding whole blood alcohol concentration would be. When we're talking about blood alcohol concentrations or blood ethanol concentrations and serum ethanol concentrations — serum ethanol concentrations are always higher than a blood alcohol concentration. If you had a blood and a serum sample that were collected from the same person at the same time, you would always expect the serum alcohol to be between 13 and 19% higher than the whole blood.

MS. KNOWLES: So for that reason — that difference between the two — this service that we offer can assist to approximate what a corresponding whole blood ethanol concentration would be based on testing of a serum ethanol concentration.

MS. KNOWLES: Yes, I did.

MS. KNOWLES: For the serum conversion, I referred to medical records that were provided with a request.

MS. KNOWLES: Yes. The flagged page is consistent with the portion of the medical records that I had reviewed in preparation for doing the serum conversion calculations for this report.

MS. KNOWLES: Yes, they do.

MS. KNOWLES: The results are recorded as an alcohol result with a value of 93 mg per deciliter.

MS. KNOWLES: The collection time listed on the medical records is January 29th, 2022 at 9:08 a.m.

MS. KNOWLES: Yes.

MS. KNOWLES: Yes.

MS. KNOWLES: So, the way that the calculation is performed is kind of in two steps. So, the results are listed in milligrams per deciliter, which is common in clinical testing. And to convert it to the type of units that are typically used for blood alcohol concentrations, we just divide by a thousand to get that into the right units. So 93 mg per deciliter converts to 0.093 g per. And then to perform the serum conversion — or to get this serum ethanol concentration into what we would estimate to be a blood alcohol concentration — we apply two conversion factors, a low and a high conversion factor, to account for the range that we see in the typical population. I'd mentioned earlier that serum is usually between 13 to 19% higher.

MS. KNOWLES: So we divide that 0.093 by 1.13 and by 1.19 to get a low and a high blood alcohol concentration for that range.

MS. KNOWLES: The conversion factors come from literature where they've performed experiments similar to how I described. They have individuals that have ingested ethanol. They collect samples from them and test their whole blood and test their serum alcohol concentrations and then compare them and see what the ratio is between them. The current ratios that are used by the laboratory — the 13 and 19% — those are also consistent with consensus body documents or sort of industry standards that we utilize and base our protocols upon.

MS. KNOWLES: There was a consensus body document published in 2024. And so we adjusted the serum conversion factors that had previously been in use to those new published recommendations in September of 2024.

MS. KNOWLES: Yeah, the previous factors — we used between 12 and 18%. And so when you perform that conversion, it typically ends up with an equivalent or lower blood alcohol concentration. And so it could be interpreted as being favorable to a defendant.

MS. KNOWLES: We don't use just one conversion factor, because in the studies that we base our procedures on it demonstrates that the general population does not have one consistent conversion factor or ratio between their whole blood and their serum alcohol concentrations. And so to ensure that the conversion that we're utilizing applies to most of the general population, we use sort of the extremes of what we see in that literature — a high and a low — to make sure that our approximation falls such that the true value would fall somewhere in between that low and that high value.

MS. KNOWLES: So the 93 mg per deciliter serum ethanol concentration would convert to between 0.078 and 0.082%, or grams percent.

MS. KNOWLES: Yes.

MS. KNOWLES: Sure. A retrograde extrapolation is another service that the laboratory offers where it's a calculation that we can perform when we have an alcohol concentration that was measured at a particular time and it would be helpful or relevant to know what that person's blood alcohol concentration was at some point prior to that sample having been collected. What we're doing with this calculation is taking what we know about how quickly the human body is capable of breaking down alcohol and applying that rate of elimination to the time interval between when the sample was collected and tested and when there might be a particular time of interest — a car accident or some interaction — where that person's blood alcohol concentration might be relevant.

MS. KNOWLES: Similar to the range of conversion factors that we were looking at with the serum conversion, we know that the rate of elimination of alcohol in humans varies from person to person. And so based on studies where they're looking at rates of elimination in large groups of people, we know that alcohol can break down at a rate of between 0.010 and 0.025% per hour. And so we take — when we're looking at a serum conversion combined with a retrograde — we take the smaller of the serum conversion range and we add that to the slowest elimination rate multiplied by a time interval. And then we also take the larger of the serum conversion values and add that to the fastest elimination rate multiplied by the time interval.

MS. KNOWLES: We use a smaller time interval for that sort of minimum calculation, to account for the fact that we don't want to overshoot that estimate of blood alcohol concentration, if there was some unabsorbed alcohol. We don't necessarily always know when we perform these calculations the drinking history or when the person had stopped drinking that day. And so we usually subtract 2 hours from the time interval when we're doing that minimum calculation to have a more conservative estimate. So we're applying the time interval, the rates of elimination, and looking at what we have for blood alcohol concentrations, all to be considered when we're performing the calculation.

MS. KNOWLES: We need to know what the blood alcohol concentration was at the time that the sample was collected. We need to know the time the sample was collected and we need to know the incident time or the time of interest that we're calculating back to. There are a couple of requirements to be able to perform this calculation that we have to ensure: we have to make sure that there's at least been two hours in that time interval between the time of collection and the time of interest that we're looking at. We can't calculate backwards with that very narrow window because we can't be sure that the person is entirely in the elimination phase — that their body has reached a maximum blood alcohol concentration and they're just breaking down alcohol at that point.

MS. KNOWLES: And we also know that this simple rate of elimination calculation can't be accurately modeled once we get down below between 0.02 and 0.03. So we have to make sure that the starting blood alcohol concentration is at least 0.03 or higher in order to be able to apply that math.

MS. KNOWLES: Generally, after someone stops drinking alcohol, their body reaches a maximum blood alcohol concentration, and then after that maximum is reached — for most folks that's between 30 and 90 minutes after they stop drinking — the body breaks the alcohol down over time in a very predictable linear fashion, down until it gets into about 0.02 and 0.03. The mechanism that the body uses to metabolize — some alcohol is excreted in urine, some alcohol is evaporated and removed from the body through your breath, but the vast majority is broken down with enzymes in your body that convert the ethanol structure into water and carbon dioxide.

MS. KNOWLES: So alcohol, once it's ingested, moves through the body in a couple of different phases. Initially, the body is absorbing alcohol. Then the alcohol is distributed throughout the body where it can have its effects. There's the metabolism phase and then elimination. Most drugs and alcohol all kind of follow that same pattern in these different phases. And I'd mentioned the elimination phase earlier — that's after you've reached a maximum blood alcohol concentration and your body is no longer absorbing. It's fully distributed in your body and then you're just breaking it down and removing — your body's removing the alcohol or the ethanol from your system.

MS. KNOWLES: So because we don't know an individual's particular rate of elimination, we use a maximum and a minimum — a fast and a slow elimination rate. And so our results for this calculation are always expressed in a range to ensure that that individual's actual blood alcohol concentration lies somewhere between the range that we provide.

MS. KNOWLES: They signify the smallest and the largest concentration that could be reasonably expected based on the blood alcohol concentration and the rates of elimination that are being applied in the calculation.

MS. KNOWLES: Yes, I was.

MS. KNOWLES: Yes, I did.

MS. KNOWLES: 12:45 a.m., January 29th, 2022.

MS. KNOWLES: I believe it was the time specified in the request from the district attorney's office.

MS. KNOWLES: Because the time interval that we use in the calculation depends on the starting and the ending point of that calculation. So the time of incident is important because that's what we're basing the math on.

MS. KNOWLES: That based on the 93 milligrams per deciliter value that was obtained at Good Samaritan, that the blood alcohol concentration for that individual at 12:45 a.m. could be between 0.14 and 0.28%.

MS. KNOWLES: Yes.

MS. KNOWLES: Good afternoon.

MS. KNOWLES: That's correct.

MS. KNOWLES: There are aspects of quality and analyst competence that are addressed in the accreditation standards. Yes.

MS. KNOWLES: Yes.

MS. KNOWLES: Yes. One of the most important requirements is an independent external review of your lab's quality management system.

MS. KNOWLES: Yes. That's definitely one important component of the accreditation process.

MS. KNOWLES: Yes.

MS. KNOWLES: Yes.

MS. KNOWLES: Yes. The review includes the procedures and the operating protocols, and there is some element of case file and specific work review within your lab.

MS. KNOWLES: Yes.

MS. KNOWLES: Yes.

MS. KNOWLES: Yes. It's an achievement that's obtained by the hard work of a lot of folks at the lab working together.

MS. KNOWLES: Correct. It's important to ensure confidence in our results, to maintain the quality and maintain the accreditation.

MS. KNOWLES: Correct. Typically accrediting bodies for clinical chemistry or hospital systems are different accrediting bodies, or different standards, than forensic standards.

MS. KNOWLES: Correct. They have different customers and sort of different scope or intention for the use of their results.

MS. KNOWLES: That's consistent with my understanding. Yes.

MS. KNOWLES: Not that I'm aware of. No.

MS. KNOWLES: Yes.

MS. KNOWLES: Correct.

MS. KNOWLES: Yes.

MS. KNOWLES: Right. It has no relationship to your crime lab, the Good Samaritan lab. Correct. The same policies and procedures are applied when our laboratory analyzes serum, or if we needed to do a retrograde extrapolation on testing that was performed internally — that's covered by the scope of accreditation. But as you're mentioning, the testing was not performed in my laboratory. I don't have any direct knowledge or understanding of their QC procedures, of their accreditation requirements, or their testing procedures at all.

MS. KNOWLES: That's accurate. The reliability of the results that my calculations were based on — my calculations are only as good as the numbers that I was provided. And like I said, the same math that I did here, I would do to my own internal standard or my own internal testing, anything that I performed testing on in the lab myself. But the results that I started from, I don't have any direct knowledge on their accuracy or reliability.