"You will now read a transcript of testimony given by Terry Smith at trial."

"Q: Please state your name. <br/>
A: Terry Smith. <br/><br/>
Q: Who do you work for? <br/>
A: The local police department. <br/><br/>
Q: What do you do for the police department? <br/>
A: I am a firearms examiner. <br/><br/>
Q: How long have you been doing that? <br/>
A: 7 years. <br/><br/>
Q: What is a firearms examiner? <br/>
A: A firearms examiner is someone who looks at cartridge cases and bullets to determine whether 
they were fired from a particular firearm. <br/><br/>
Q: What training is required to become a firearms examiner with the local police department? <br/>
A: I received my bachelor's degree in forensic science and in 2015 I transferred to the crime lab 
from the crime scene unit. I underwent a two-year training program, which was supervised by experienced 
firearms examiners; I've toured manufacturing facilities and saw how firearms and ammunition were produced; 
and I've attended several national and regional meetings of firearms examiners."

"Q: And during the course of your career, were you tested in proficiency to make sure you were still conducting
appropriate examinations? <br/>
A: Yes. I have undergone annual proficiency examinations. <br/><br/>
Q: Is the local police department lab accredited? <br/>
A: Yes, it is accredited by ASCLID/LAB. <br/><br/>
Prosecution: Your Honor, at this time I would ask that Terry Smith be qualified as an expert in the field of 
firearms identification subject to cross examination. <br/>
Court: Any cross on their credentials? <br/>
Defense: No, Your Honor. <br/>
Court: This witness is an expert in the area of firearms identification. They can testify to their opinions as 
well as facts. Go ahead."

"Q: What work did you do on this case? <br/>
A: I was asked to compare a bullet from the crime scene to a test fire from the gun recovered from the traffic stop. <br/><br/>
Q: Did you examine how many lands and grooves the bullet had? <br/>
A: Yes. <br/><br/>
Q: Can you explain for the jury what that means? <br/>
A: Yes. In the interior of a barrel there are raised portions called lands and depressed areas called grooves. 
When a bullet passes down the barrel, a bullet will spin and that gives it stability and accuracy over a distance. 
Those raised areas are designed by the manufacturer. They're cut into the barrel. And each particular file has a 
different combination of lands and grooves. But essentially what those lands do is grip a bullet and spin it, and 
as that bullet passes down the barrel, it scratches the random imperfections of that barrel into the bullet."

"Q: Now, for these bullets, you counted up the lands and grooves and determined the direction of the twist, correct? <br/>
A: Yes. This bullet had six lands. And the interior of the barrel, the barrel will either twist right or it will twist left. 
And in this particular case, the barrel twists right. And you can see that by looking at the bullet. If you look at the base 
of the bullet, either it goes to the left or goes to the right. 
Exhibit A depicts a cross-section of a barrel, where rifling is clearly present. Exhibit B depicts an example of a 
fired bullet, with which includes lands and grooves.<br/>
<center>---Exhibit A---</center><br/>
<img src=\"rifling.jpg\" alt=\"rifling\" style=\"width: 50%\" height=\"\" class=\"center\"><br/><br/>
<center>---Exhibit B---</center><br/>
<img src=\"fired_bullet.jpg\" alt=\"fired_bullet\" style=\"width: 50%\" height=\"\" class=\"center\"><br/>

<br/><br/><center>---Test-fired bullets admitted into evidence---</center><br/><br/>
Q: Can you describe the process of obtaining these test-fired bullets? <br/>
A: The test-fired bullets came from a test fire of the gun recovered from the traffic stop. <br/><br/>
Q: You mentioned test firings; can you explain what that means? <br/>
A: In test firing, first what I would do is make sure the firearm is safe to actually test fire. Then
I would use lab ammunition and I would test fire it, meaning that I am creating a fired bullet. Typically
you do two at a time. That way you have a fired bullet to compare to another fired bullet. <br/><br/>
Q: Would you then have taken the test firings you created and did you compare those test firings to the
fired evidence that you had also received?<br/>
A: Yes. First what I would do is compare my test shot to test shot. I am looking for a detailed
microscopic pattern. Once I have done that then I would compare it to the fired evidence. <br/><br/>

Q: And how about the number of lands and direction of twist for the test fires? <br/>
A: It also had six lands, and twisted to the right. <br/><br/>
Q: Okay. Now, did you compare the test-fired bullets to the fired evidence under the comparison microscope? <br/>
A: Yes, I did. <br/><br/>
Q: What is your conclusion? <br/>
A: I found that there were sufficient individualizing characteristics to make an identification, that is that the two bullets were fired from
the same barrel."

"Q: How were you able to conclude that? <br/>
A: I place them under the comparison microscope, and I roll the bullet around until I can see the agreement in a particular 
area: unique surface contour that has sufficient agreement. At that point, when I've seen that, I start to rotate the bullets 
around and I look at all the different lands and grooves, impressions, for that unique detail. When I can see those, that agreement 
on multiple areas of the bullet, I identify the bullet as having sufficient agreement. 
Exhibit C shows an image of a comparison microscope, as well an an example of a matching bullet comparison. <br/>
<center>---Exhibit C---</center><br/>
<img src=\"microscope.jpg\" alt=\"microscope\" style=\"width: 50%\" height=\"\" class=\"center\"><br/>
Q: Now, how many times have you compared bullets to determine if they were fired from the same gun? <br/>
A: I'd say thousands. <br/><br/>
Q: And do you ever see two bullets that have agreement in every single area of the bullet? <br/>
A: No. When firing a firearm there is a dynamic process because it is a contained explosion. When the firing pin hits the primer, which is 
basically the initiator, what gets it going, it will explode, burn the gun powder inside the casing, and the bullet will travel down
the barrel, picking up the microscopic imperfections of the barrel, and the cartridge case will slam rearward against the support 
mechanism. During that dynamic process, each time it happens, a bullet will be marked slightly differently from one to the next. <br/><br/>
Q: When you reached a conclusion, did you write up a report? <br/>
A: Yes, I did. <br/><br/>
Q: Is it the local police department's protocol to have somebody else who's a firearms tool mark examiner in your lab review that report, 
review your work, and determine if it's correct? <br/>
A: Yes. <br/><br/>
Q: That's what we call peer review? <br/>
A: Peer review, yes. <br/><br/>
Q: Thank you, no further questions."

"<center>---Cross Examination---</center><br/>
Q: Now, are you telling the jury today that in your opinion there's only one gun in the entire world that could have produced the markings
that you saw on these bullets? <br/>
A: I'm saying that the probability that the two markings were made by different sources is so small that it
is negligible. <br/><br/>
Q: Exclusive to any other gun? <br/>
A: I obviously haven't tested every other gun, but the probability is negligible. <br/><br/>
Q: That's your opinion. And your opinion, by the way, is subjective, right? And it's based on your experience? <br/>
A: Based on my training and experience, yes. <br/><br/>
Q: Is there something fixed about the amount of what has to be found to constitute sufficient agreement? <br/>
A: No, there is not a fixed amount or a numerical value.<br/><br/>

<center>---Questions Submitted By the Jury---</center><br/>
The Court: Terry Smith, the jury has asked me to forward this question to you. Answer if you're able.
To what percentage is the science accurate is the first question. And then I think the rest of that explanation of that 
question goes on to say, to determine that the bullets were fired from the same firearm, are you 100 percent sure? <br/>
A: My opinion, I am 100 percent sure that these bullets were fired from this firearm. There is a published error
rate for firearms examiners. The false positive identification rate is less than two percent. I believe it's about 1.5 to 1.9.
That's just a general number that's out there."