3.Meredith McCaskill — Direct/Cross
150 linesDIRECT EXAMINATION
BY MR. JAY:
MEREDITH MCCASKILL: I'm employed at the Florida Department of Law Enforcement, the Orlando Regional Operations Center.
MEREDITH MCCASKILL: Yes, it is.
MEREDITH MCCASKILL: I am a senior crime laboratory analyst in the biology/DNA section.
MR. JAY: Now, what is your educational background -- and we'll get into training and experience as well, but what's your educational background that allows you to do that job?
MEREDITH MCCASKILL: I have a bachelor of science in biological sciences from Clemson University and a master of science in biomedical forensic science from the Boston University School of Medicine.
MEREDITH MCCASKILL: I started at FDLE in April of 2011.
MR. JAY: And did you have any prior work experience as a forensic examiner of blood or biological or DNA evidence?
MEREDITH MCCASKILL: No, I did not.
MEREDITH MCCASKILL: Yes, that's correct.
MR. JAY: And do you have any sort of in-house training and then continuing education that goes on as an employee at FDLE?
MEREDITH MCCASKILL: Yes. So when you become a crime laboratory analyst, you have to successfully complete a training program. This training program takes about a year and a half to two years. It covers all of our policies and procedures and manuals, reading textbooks and scientific articles, and performing a lot of in-house testing and training under the supervision of a qualified analyst. There's also written and oral examinations, and you have to successfully complete every part of that in order to work cases as a crime laboratory analyst. And then every year we have continuing education, so that's education that we need to do in order to stay current with new trends and technologies in the field.
MR. JAY: Does the lab itself enjoy any accreditations? And what process, if so, does it go through to get them?
MEREDITH MCCASKILL: Yes. FDLE is accredited by an organization called ANAB, it's the American National Standards Institute, National Accreditation Board. So we've been accredited for, I believe, over 30 years. It's a process where every four years they send people to come and inspect our lab; make sure that we're doing everything that we're supposed to be doing according to our policies and procedures. And then we're also following national standards that have been sent down. That's every four years. It's very in-depth. And then we have additional kind of, like, spot-checks every year just to make sure that we are maintaining everything that we are supposed to be doing.
MR. JAY: Have you ever given testimony in court about your opinion about serology analysis or DNA analysis?
MEREDITH MCCASKILL: Yes, I have.
MEREDITH MCCASKILL: Approximately, 35 to 40 times.
MEREDITH MCCASKILL: No, I have not.
MR. JAY: Can you tell us about the place -- particularly within FDLE, tell us about your workspace and what personal protection equipment you may wear when you're doing DNA analysis.
MEREDITH MCCASKILL: Yes. So in my workspace, I have what I call a clean side, which is where I keep all of my paperwork, and then I have my other side, which is used for actual screening of evidence items. So this is a surface where I can clean it with a detergent. I clean all of the instruments that I'm using, so scissors, markers to take notes, anything like that is cleaned with a detergent, both before I start and after I finish, and it's cleaned and maintained in between every item of evidence. So only one item of evidence is open at a time, and this is to minimize any potential contamination, so DNA from one item getting into DNA from a second item.
I also wear what is called personal protective equipment. This includes a lab coat, face mask, gloves, and potentially a hairnet, depending on what type of evidence that I'm working with. And then the gloves are disposable, so they are changed before and after each item of evidence. It's also changed if I have to touch my computer to take notes, I change my gloves. If I have to touch another surface, I change my gloves. So it's a lot of procedures that we use in order to prevent my DNA from getting onto the item of evidence.
MEREDITH MCCASKILL: Yes. We have an instrument platform that we use that allows us to run the DNA in batches in an efficient manner, so there's multiple instruments that are used across the varying processes.
MR. JAY: And do these instruments generate paperwork that humans, such as yourself, can then go read and interpret?
MEREDITH MCCASKILL: Yes, it does.
MR. JAY: Now, in this particular case, you were not the analyst who examined the items; is that correct?
MEREDITH MCCASKILL: Yes, that's correct.
MR. JAY: Did you review the information that is generated by the instruments used by the analyst who did this work in coming to your own conclusions?
MEREDITH MCCASKILL: I was the technical reviewer on this file, so I reviewed all of the documentation and the paperwork and also the original analyst report.
MR. JAY: All right. Now, one of the items that is said to have been analyzed was a DNA card. Are you familiar with what that is?
MEREDITH MCCASKILL: Yes, I am.
MEREDITH MCCASKILL: Usually it's referred to as a DNA card or a bloodstain card, and that's just a card where somebody can spot blood, usually human blood, on it and dry it down. Then the analyst can take a cutting of that stained area in order to generate a DNA profile.
MR. JAY: And is that typically the manner in which a decedent or a dead person's DNA sample is provided to the lab for analysis?
MEREDITH MCCASKILL: Yes. That's a very common thing that we see in decedents.
MR. JAY: And can you explain to the jury how it is an analyst, such as yourself, would take that bloodstain on a portion of the DNA card and develop a DNA profile?
MEREDITH MCCASKILL: Yes. So it usually is blood stained on the card, so you can identify that stain visually, take a cutting of that stained area and then place that cutting into a sterile tube, which is then sent through the DNA process. So that's adding chemicals and heat in order to break the cells open and release the DNA into the solution. And then running it through the rest of the procedures where we determine about how much DNA is in the sample, make millions of copies of our specific areas of interest, and then generate a DNA profile that can be used for comparison to any questioned items in the case.
MR. JAY: Do you use some sort of commercial kit to develop DNA profiles on known items, such as this?
MEREDITH MCCASKILL: Yes, we do.
MEREDITH MCCASKILL: In 2020, it was 21 locations.
MR. JAY: All right. And in going through this process, is there a process that amplifies the amount of DNA?
MEREDITH MCCASKILL: Yes, there is.
MEREDITH MCCASKILL: Yes. So we need to amplify or make millions of copies of the specific areas of interest that we're looking for. We don't want to make copies of the entire DNA molecule. We're just wanting to isolate those specific 21 areas and make copies of those specific areas in order to generate the DNA profile that we use in forensic DNA analysis.
MEREDITH MCCASKILL: Yes, I do.
MEREDITH MCCASKILL: A short tandem repeat -- we also call them STRs -- that's just what we're looking for in the forensic DNA analysis. They are small -- short areas of repeating DNA pieces. So, for example, at somebody's DNA profile at a specific location, you can have a set of 16 repeats and a set of 17 repeats, and that's just this one little piece of DNA and it repeats 16 times and then you have a piece that repeats 17 times, and it's the number of repeats that is different from person to person.
MR. JAY: And you said you might be a 16 at one spot and 17. Let's just be clear what we're talking about. On one particular location -- well, all of them -- do you get DNA from mom and dad and can you explain that?
MEREDITH MCCASKILL: Yes. So you get DNA from your parents, so it's inherited. You get half of your DNA from your mom and half from your dad. So when I'm talking about the short tandem repeats and the example of a 16 and a17, that could mean that you got a set of 16 repeats from one parent and a set of 17 repeats from the other parent, so it's just the copies that you get from your parents.
MEREDITH MCCASKILL: Yes. That's also a possibility.
MEREDITH MCCASKILL: Yes. So there's 21, and then we look at several areas that are on the gender marker, so it was three areas on the gender markers.
MR. JAY: And each of these locations will come up with some sort of number, like 16-17, 4-4, so on and so forth?
MEREDITH MCCASKILL: Yes, that's correct.
MR. JAY: In reviewing the instrumentation data in this case, was the DNA profile that was said to have come from Mr. Torres, was there able to be a full DNA profile at those 21 locations developed?
MEREDITH MCCASKILL: Yes. A complete profile was obtained for that sample.
MR. JAY: Now, can you tell us what a buccal or a buccal swab -- sometimes people call it each. Which way is the right way?
MEREDITH MCCASKILL: T usually use the word buccal, but buccal is not incorrect either.
MEREDITH MCCASKILL: It's just a swab that we can use as a reference sample from a person. So it looks -- all of our swabs just kind of look like a long Q-tip with only one end, and then you just take that cotton tip end and rub it on the interior of your mouth to get a good DNA sample. You have a lot of cells on the inside of your mouth and a lot of saliva, so that's a good source to use for a known sample from a person.
MR. JAY: And these long Q-tips, I believe as you described, are they put into a box that is designed in a way so that the Q-tip doesn't touch the edges of the box?
MEREDITH MCCASKILL: Yes. I've seen it in boxes like that, but I have also seen it where they've been put back into the original paper packet container. So either -- either method is fine.
MR. JAY: And did the FDLE in this particular case and the data that you reviewed, was there buccal swabs represented as being from the defendant, Sarah Boone?
MEREDITH MCCASKILL: Yes, there was.
MR. JAY: And in the process that you've briefly described for the jury already, can you -- can you just tell us, if it's different in any way, to take a part of that cotton swab to develop a DNA profile than a piece of the DNA paper?
MEREDITH MCCASKILL: No. It's the same process. With the buccal swabs, I'm just taking a small cutting of the cotton area of the swab, placing it in a tube, and then running it through the exact same DNA process.
MR. JAY: And was a full profile at the 21 locations able to be developed for the buccal swabs represented as being from Ms. Boone?
MEREDITH MCCASKILL: Yes. A complete profile was obtained for that sample.
MEREDITH MCCASKILL: Yes, there were.
MR. JAY: And you can -- can you describe the difference between a known and an unknown sample for the jury?
MEREDITH MCCASKILL: Yes. A known sample is a sample from a specific person. So that's like the example of a buccal swab, I know that sample came from that individual and I can use that as a way to determine that particular person's DNA profile. An unknown sample, it's just a sample where we don't know whose DNA or if there is any DNA on that sample at all, so those are questioned items that can be -- once a DNA profile is obtained from that item, can be compared to the known profiles obtained from individuals.
MR. JAY: And in this case, was there an unknown item labeled as DNA swabs represented as coming from Mr. Torres' fingernails?
MEREDITH MCCASKILL: I believe it was fingernail clippings --
MEREDITH MCCASKILL: -- from Mr. Torres, yes.
MR. JAY: All right. And, typically -- I know you didn't do the work on this particular case, but in reviewing the notes and in your experience, do these DNA samples from fingernail clippings come in as swabs, like a buccal swab?
MEREDITH MCCASKILL: So sometimes they can come in as swabs, but other times they come in as just fingernail clippings, so taking the clippers and just cutting off the ends of the fingernails. And then I've also seen it where they've been scraped using pointed sticks.
MR. JAY: And so if there is a swab that came in represented as being from the fingernails, then that would go through the process as you've previously described for the buccal swabs?
MEREDITH MCCASKILL: Yes, that's correct.
MEREDITH MCCASKILL: Yes, that's correct.
MEREDITH MCCASKILL: We have prepackaged swabs in our lab. We can then use some sterile deionized water and drip that onto the end of the cotton tip to make it a little bit moist so that it can pick up any DNA that is left on the item. And then we just swab the surface of the item, allow the swab to dry, and then cut it and place it into a tube for the DNA process. So we're just making our own swabs at that point.
MR. JAY: And was there a profile obtained from what was represented as being the DNA samples from Mr. Torres' fingernail clippings?
MEREDITH MCCASKILL: Yes, there was.
MR. JAY: And did it match either of the two known profiles that we've just discussed here this morning?
MEREDITH MCCASKILL: Yes, it did.
MEREDITH MCCASKILL: Mr. Torres.
MEREDITH MCCASKILL: No. There were no DNA results foreign to Mr. Torres obtained from either set of fingernail clippings.
MR. JAY: Likewise, was there something examined in this case represented to be swabs or DNA samples from Ms. Boone, the defendant's fingernails?
MEREDITH MCCASKILL: Yes. Those were swabs that were sent represented as being from her fingernails.
MR. JAY: And so just like the buccal swabs, they come in as a Q-tip and then you would test that in a similar manner?
MEREDITH MCCASKILL: Yes, that's correct.
MR. JAY: Was a profile able to be developed from what was represented as being swabs from Ms. Boone's fingernails?
MEREDITH MCCASKILL: Yes, there was.
MR. JAY: And did that profile match either of the two known profiles that we've been discussing this morning?
MEREDITH MCCASKILL: Yes, it did.
MEREDITH MCCASKILL: Ms. Boone's.
MR. JAY: Now, in regards to both of these last items that we've talked about, the fingernail swabs from each Mr. Torres and Ms. Boone, is it -- is it expected that their profile would be developed from DNA swabs from their fingernails?
MEREDITH MCCASKILL: Yes, it is. Both are -- all of those samples were represented as being from those particular individuals, so their DNA is expected to be on those items.
MR. JAY: Was there any DNA foreign to Ms. Boone on those samples that were represented as coming from her fingernails?
MEREDITH MCCASKILL: No. There were no DNA results foreign to Ms. Boone obtained from either set of fingernail swabs.
MEREDITH MCCASKILL: Yes, it is.
MR. JAY: How sensitive is it when, you know, a sample is taken from an unknown area, such as fingernails?
MEREDITH MCCASKILL: The PCR process is pretty sensitive. And over the years, as the science has evolved and testing has changed, the process has become even more sensitive over the years.
MR. JAY: And, hypothetically, if two people are living together and are intimate partners, quite frankly, would you expect the intimate partner's DNA to show up on swabbings from their fingernails?
MEREDITH MCCASKILL: Yes. It's possible that their DNA would show up if they're in close contact with each other.
MR. JAY: But in this particular case, after reviewing all of the instrumentation data, there was no DNA foreign to either of their fingernail clippers -- clippings or swabs from their fingernails, both Mr. Torres and Ms. Boone?
MEREDITH MCCASKILL: Yes, that's correct.
THE COURT: Any cross-examination?
CROSS -EXAMINATION
BY MR. HENDERSON:
MR. HENDERSON: Good morning, ma'am.
MEREDITH MCCASKILL: Good morning.
MR. HENDERSON: Once you develop a profile, are you able to take that profile and compare it to other possible DNA on objects or items?
MEREDITH MCCASKILL: Well, if it's a DNA profile that is obtained from a questioned item, we can compare that to profiles from known individuals.
MR. HENDERSON: Okay. And in this case, an example of that, if an object from an unknown source, you could take that and compare it to a known profile; is that correct?
MEREDITH MCCASKILL: Yes, that's correct.
MR. HENDERSON: And if you get a match with that comparison, what can you take from that?
MEREDITH MCCASKILL: Just that that is -- the DNA profiles are the same.
MR. HENDERSON: So if it's an object, let's say, like a bat, and there's a DNA profile that's obtained from the bat and it matches a known profile, could you make the conclusion that the -- that person touched or handled that bat from the known profile?
MEREDITH MCCASKILL: No. I can't -- there's nothing in the testing that we do at FDLE that will allow me to determine how any DNA ended up on an object or how long it's been on that object.
MR. HENDERSON: Okay. Now, you said that in this case, what was sent for DNA comparison?
MEREDITH MCCASKILL: In this case, there were -- it was a bloodstain card or a DNA card represented as being from Mr. Torres, buccal swabs represented as being from Ms. Boone, fingernail clippings from both hands represented as being from Mr. Torres, and then fingernail swabs from both hands represented as being from Ms. Boone.
MR. HENDERSON: Those are the only items that were sent to your lab for comparison?
MEREDITH MCCASKILL: Those were the only items sent to the DNA lab, yes.
MR. HENDERSON: Okay. Thank you, ma'am.
I have no further questions.
THE COURT: Any redirect examination?
THE COURT: Defense?
MR. OWENS: Yes.
THE COURT: All right. Ma'am, you're excused. Thank you very much.
MEREDITH MCCASKILL: All right. Thank you.
(Witness excused.)