Unredacted Episode 4: Transcript of Interview with Don Thomas
Don Thomas is the scientist whose work on the Kennedy assassination acoustics evidence has made a strong challenge to the "debunking" the HSCA's acoustics analysis received in the early 1980s. This interview was conducted on 5 Apr 2006. Tyler Weaver provided the introduction, and the interview was conducted by Rex Bradford.
TYLER: Hi there, and welcome to the newest episode of Unredacted, here at maryferrell.org. Apologies for the delay between this episode and the last, but we've been hard at work around here with our ongoing project of digitizing the AARC's collection of CIA documents for your browsing and searching pleasure.
Just to refresh memories a bit, my name's Tyler Weaver, and for this episode we've got an exclusive interview with Don Thomas, renowned acoustics expert and author of several articles that have appeared in "Science and Justice," most notably 2001's "Echo Correlation Analysis and the Acoustic Evidence in the Kennedy Assassination Revisited."
This interview with Don was recorded in June, and is conducted by my co-host, Rex Bradford. So, I'll sign off for now, and turn it over to Rex. Enjoy.
REX: Alright, this is Rex Bradford; we're here with Don Thomas, who published an essay in "Science and Justice" in 2001, which revived the debate on the acoustics evidence in the Kennedy assassination. Hi, Don.
DON: Hello, Rex.
REX: Um, I'd like to start just by asking how you came to write that article and just give us a brief introduction as to what it's all about.
DON: Well, I was interested in all aspects of the Kennedy assassination, most particularly in the forensic evidence, because I'm a scientist by profession and therefore tend to put more faith in hard evidence and the scientific analysis of evidence. One of the aspects of the evidence that stood out, I suppose, was the acoustical evidence. It had been criticized strongly, and actually I had written up a huge manuscript dealing with all the forensic evidence, searched around for a publisher - no one was interested - and then I backed off, and said "Well, I guess the way to approach this is to go the scientific journals," and so happens I started with the acoustics evidence, and as far as - to give you, I guess, a basic outline of what the forensic evidence shows, I know there's a little bit of confusion because the House Select Committee on Assassinations - I should say that I'm not an acoustics expert myself - uh, the House Select Committee on Assassinations hired acoustical experts to analyze a recording that was made by the Dallas Police at the time of the assassination.
It was actually - to back off - it was Mary Ferrell - who was the one actually brought attention to the House Select Committee on Assassinations that this recording existed, and that there was a possibility that the sounds of gunfire was on the recording. And, as it turns out, the acoustical experts, both Bolt Beranek and Newman, same folks who had done the Watergate tapes, perhaps more importantly they had done the Kent State shooting tapes, analyzed the recording and found evidence for gunfire on the recording.
REX: Right, so they ended up coming up with shots on the tape, including a shot from the "Grassy Knoll," which was one of the factors which led the HSCA to their probable conspiracy conclusion, right?
DON: (coughs) Excuse me, right.
REX: So, I want to fast forward back to your work, I mean, that HSCA acoustics evidence was reportedly debunked, first by a FBI report, then by the Ramsey Panel appointed by the National Academy of Sciences in the early eighties. It sat there for quite a while. I'm curious, when did you first start picking up on that thread?
DON: I guess it was really, it was right after the movie JFK came out - Oliver Stone. Up 'til that time, I had no interest in the Kennedy assassination, and actually before seeing the movie, it was really an article by Newsweek that attacked the movie. I was really struck by that, because here was a six-page cover story article which was entitled "Twisted History," claiming that Oliver Stone's movie was - implying at least - that it was a pack of lies, and yet in the entire article, they did not cite a single example of a falsehood or an untruth - an error - and that struck me as odd. So I started reading about the assassination, and of course, I got especially interested in the scientific evidence, and that led into the - eventually - working on the acoustics evidence.
REX: And your expertise is statistics, primarily, although it sounds like you've branched out into a more full analysis than just running the numbers on that, right?
DON: Yeah, the statistical analysis was one part of it that it was - the House Select Commi - I'm sorry, the National Research Council - had been asked to uh - by the FBI - to review - by the Justice Department - to review the work that was done by the acoustical experts. If I could elaborate on that slightly, you mentioned the FBI study and the NRC study, actually came to kind of different conclusions.
I should point out that the work that was originally done by BBN, when they concluded that they had found the gunshots, the House Select Committee itself asked for a second opinion, so they had the Computer Science Department at Queens College - folks that are sonar experts - to review the evidence. They confirmed and actually extended the study to show that there was a gunshot from the Grassy Knoll among the shots that were identified by BBN. Now, the explanation for what is happening here is - the approach to trying to debunk that evidence by - first by the FBI - well, pretty much simultaneously, the FBI and NRC panel kind of worked together on this, and yet came to different conclusions. The NRC panel, their primary argument was that these sounds are not synchronous with the time of the assassination. That is, the sounds acoustically identified as gunfire, they claim were recorded about sixty seconds after the assassination.
The FBI report, on the other hand, its approach was that, "yes, these might be the sounds of gunfire that killed President Kennedy, but mixed among these might be a vehicle backfire, or big firecracker, or some other sound mixed in there." That would explain the Grassy Knoll shot- supposed Grassy Knoll shot. So, the debunking by the two different groups were actually quite different.
REX: Sure. OK, I'd like to come back a little later in our talk to some of those questions, because you have detractors in 2006, and that it's still controversial. But first, I'd like to say that, let's assume in fact that this is true - that your analysis based on the HSCA's earlier work of the gunfire occurred as it did, and let's just explore what that really means. I'd like to go through the shot sequence in fact, and also talk about some of the corraborating evidence, things like the jiggle analysis.
Why don't we start there? I mean, the acoustics evidence itself doesn't stand alone, and it seems like it's corroborated by analysis of the Zapruder film. Can you elaborate on that?
DON: Sure, that's exactly right. It should be emphasized that it's not just the acoustical matching. The fact that they went to Dealey Plaza, fired test shots, and that those test shots were shown to match to the sounds that are on the police tape. It was the fact that they actually matched in order - there was order in the data. And that's important, because that serves as a test that we can go back and use filmed evidence to see if that sequence is actually something that is sensible. Now that -
REX: I'm sorry, by order in the data, you mean where the open microphone that was apparently on a police motorcycle - where that was located from one sequence to the next?
DON: Right. Exactly. On the recording itself, what you hear on the police recording - for about five and a half minutes - you can hear the sound of a motorcycle motor. So what had happened, on the police channel - which was used for normal communications, for five and a half minutes you're essentially jammed, by - somewhere in Dallas - a microphone on a motorcycle cop's radio has jammed open, so you hear the sound of a motorcycle motor.
You also hear - on the recording - you also hear sirens. And this is the clue that led people to think that this was the assassination - that this was the motorcycle that was with the motorcade at the time of the assassination because the one event that was happening, the one emergency that would require sirens was the fact that the President's motorcade was on its way to Parkland Hospital immediately after the assassination.
Now, as far as the order of the data is concerned, when the acoustical experts did their matching procedure, it would be important to know exactly where the motorcycle was relative to the buildings because the patterns - the sound patterns - that are on the tape are presumed to be echoes - echoes off of the buildings in Dealey Plaza. And so the position of the shooter, the position of the microphone are important in determining whether or not you really have a match.
Now, since the acoustical experts didn't know where the motorcycle was, but they did know that the motorcade was first on Houston Street and then on Elm Street, what they did was they put out an array of 36 microphones in a row - in a line - on Houston Street and then on Elm Street. Now, that gives you essentially 36 different patterns for every test shot that you fire. And since they fired test shots from both the Book Depository and the Grassy Knoll, you wind up with a total of 72 different test patterns. That of course, will increase the chances or odds of getting a match to the patterns that are on a police recording.
Now, if by chance, you happen to get a match, and then, by chance, you happen to get all five of the sounds, because five of the sounds of the police recording matched the test shots fired in Dealey Plaza. They should be a nonsensical order if these are not Dealey Plaza echo patterns. Now since you have 36 microphone locations, if you had five matches, they would be in random order, but if they are the gunshots that killed President Kennedy, they will have to be in, uh -
REX: Right, in the order of the direction -
DON: In chronological order as the topological order of the microphones, and that's what happened. The very first sound on the recording that matched with a test shot matched to a microphone near the intersection of Houston and Elm Street. The second one matched at the intersection itself, and then third one matched slightly - the very next microphone in order, which was slightly up Elm Street from Houston. Then the fourth and the fifth matched at two microphone locations about 80 feet further up on Elm Street. So they were ordered in respect to numerical order, the chronological order matched the numerical order. But not just the one, two, three, four, five chronological order - the actual spacing was the same. By that, I mean on the tape recording the five sounds, the first three are close together, about a second apart. Then there's a five second gap, and you have two more sounds, about a second apart.
On the street, where you had your microphones, it was three microphones in a row near the intersection of Elm and Houston, and then you skipped about 80 feet - you skipped four microphones, and then you had two microphones next to each other had the last two shots. So the spacing matched - the topological spacing matched the spacing on the recording.
REX: That seems -
DON: And then -
REX: I'm sorry - that seems pretty powerful. I'm curious if there's been a counter argument to that or whether that's -
DON: No, this argument's never been countered. In fact, it's not just the spacing and the order, it's the trajectory, because the spacing between the first microphone match and the last microphone match was about a hundred and thirty feet. And the time on the recording between the first shot and the last shot is eight point three seconds.
Now, in order to go 130 feet in 8.3 seconds, you would have a speed of approximately 12 miles an hour. We know that the Zapruder film show that the President's limousine was going 11.5 miles an hour on Houston Street. So, you have a precise match in the trajectory which was demonstrated by the order of the matching that is completely non-random. It's really that order in the data that convinced the acoustical experts, and not just the matching, that these were the gunshots that killed President Kennedy.
And, of course, this provides us with a test, because now we can go back to the films of Dealey Plaza during the time of the assassination, and look for a motorcycle, and see if there was a motorcycle at the right place and the right time that was predicted by this acoustical evidence. And when they do, they find this, out of the 18 motorcycles that were in the motorcade, the filmed evidence eliminates all but one guy, a police officer named McLaine.
And it turns out that when he was interviewed by the House Select Committee, he was asked, "have you ever had any problems with this radio system?" and he said, "yeah, my microphone used to stick open on me all the time."
So, you know, this sort of evidence, where you have - where you can pinpoint the motorcycle - now I should say that we don't - the evidence is not strong enough to say he's exactly at the right spots, because what the films show, they show him a few seconds before the shooting, and they show him about 15 seconds after the shooting.
From his position, we can say that he is the one cop that was in the right place - that he could have been in the right place at the right time.
REX: Mmhm. OK. Let's um, move on to another piece of corroborating evidence, which is the so-called "jiggle analysis" in the Zapruder film.
REX: From a paper of yours that you've written on this, it seems like there's a pretty good - although not a hundred percent perfect - match there as well. Do you want to discuss how that - how the jiggle analysis lines up?
DON: Yeah, sure. There's been actually uh - on the Zapruder film, you can see places where people have been shot. I mean, you can see obviously Kennedy - it's very graphic where President Kennedy is struck in the head at Zapruder frame 313. The one other person who was shot during the assassination of course was Governor Connally, who received a wound through his chest.
Micrographic analysis of the Zapruder film by - who is it? - Failure Analysis Associated, I think it was back in about 2000 - about 1992. They showed that Governor Connally's lapel flaps at frame 224. Now at the separation in time between - and I should say immediately after that, you see Governor Connally goes into anguish - you can see he's obviously been hit. So that lapel flap would seem to indicate the actual time of impact when the bullet went through him. Now the separation in time between frame 224 and frame 313, the two places where we see people get hit, is four point eight seconds. On the police tape, the separation between the third shot and the fourth shot, which is from the Grassy Knoll is exactly four point eight seconds.
So you have a good mesh between the actual wounding sequence and the two that we would assume - the bullets that we would assume were the ones that hit Connally and the one that hit Kennedy because of the head shot certainly would have come from the Grassy Knoll.
REX: In both those places, aren't there also - Zapruder's film camera shakes, as if he's reacting to the sound as well. I'm curious - one the things I wanted to bring up about that, that you pointed out in an essay that you wrote called "Hear No Evil," was that the House Committee of course determined that, based on their medical evidence, which was telling them that Kennedy was hit by bullets only from behind, that I think they did a different alignment than you have done as to which shots match the frames in the Zapruder film...
REX: and also, in their analysis of the jiggles in the Zapruder camera - the one obvious one to explain is why there is one at frame 313, and uh, you brought up that if that shot - the shot that killed Kennedy by hitting him in the head had come from the Book Depository, the sound wouldn't have reached Zapruder in time to cause him to make that motion. Can you elaborate on that?
DON: Sure. There's several points there, because when the House Select Committee did their synchronization, one of the people that was involved in that was Bob Groden, and he had told me that he complained to them - and it was obvious that their synchronization didn't really work when they were trying to claim that the shot - those last two shots - one at frame 313 and there's one at about frame 325 - and they were trying to claim that the one at 325 must have been the -
REX: Grassy Knoll shot?
DON: The one that killed him. It came from the Book Depository. Of course, when you do that, you don't get a synchronization (laughs) between the wounding and the sounds. But, uh, Groden told me - and you can interview him sometime - that they told him basically to shut up when he pointed this out.
But the interesting thing is, if you look at the testimony of the acoustical experts, they were also asked to participate in this, and in their - at one point, one of the congressmen asked - I believe it was Mark Weiss - if he could calculate the caliber of the bullet from the gunshot pattern, and he said yeah, he could, but he'd rather not get into that. And they asked him why not, and he said, "well, because if you - you can calculate it if you know what the trajectory of the bullet is, but that gets into that non-acoustical evidence, and I don't want to get into that." And of course, the non-acoustical evidence was the claim that the shot didn't hit him in the head.
If the shot from the Grassy Knoll's the one that hit him in the head, you know exactly what the trajectory is, and it's easy to calculate what the caliber of the bullet is, and Weiss knew that, and it was clear from that conversation that Weiss probably wasn't entirely buying their argument, that the shot that killed him probably did come from the Grassy Knoll.
REX: You picked up that very point later, the caliber of the bullet?
DON: Yeah, in fact, I published that in "Science and Justice." I went ahead and calculated the caliber of the gun from that -
REX: And what was it?
DON: - from a shockwave prescedence. It... it comes out to about 2600 feet per second is the muzzle velocity, and so that corresponds to the - that muzzle velocity corresponds to a 30/30.
REX: Uh-huh. Let's go back to the shot sequence as it's defined by this evidence. The first of five shots that's identified is around Zapruder frame 175, and -
REX: - and, um, you have an interesting theory about that shot and what happened with it. The idea that it was a missed shot and it kicked up some shrapnel?
DON: The one - yeah? The shot at 175?
DON: Right, exactly, yeah.
REX: I just thought that -
DON: Because -
REX: Go ahead.
DON: Yeah, shortly - and actually, I have to give credit to the very first forensic panel that examined the evidence - the Fisher Panel - that looked at the autopsy photos and the x-rays, and they're the ones who noticed that large metal fragment that's in the back of the President's head. And they - that panel - thoughts that, "gee, that looks like a shrapnel fragment" - and of course, they didn't put that in their report, this came out later in an interview with Dr. Fisher.
And, that struck me, and I realized that, well, yeah, that's explains why the wound in the back of the head through the scalp was tunneling an upwards slant - you know, slanting, uh, uh - how did they describe this - a laceration in the back of the skull, which exactly would fit. And, going back and reading the testimony of the eyewitnesses who were standing in front of the limousine - in front of the Book Depository - and how several of them said they had seen something hit the street next to the limousine.
REX: Sure. Many more people - including those that (weren't) familiar with firearms - talked about the first shot being a firecracker. I wonder if the sound of hitting pavement might bring that impression on them?
DON: Yeah, it's hard to tell what peoples' impression of sound. Yeah, a lot of them felt the first shot sounded more like a firecracker, and that gets more into another problem, another issue.
But, the other part about the shrapnel was that Kennedy - his first reaction was to suddenly flinch. You know, he jerked forward, he brought his arms up in front of his body, and shook his head back and forth. And then, according to the Secret Service agent who was in the car, he heard Kennedy say, "my God, I'm hit!"
All of which taken together, you know, not just one thing, all taken together, it sure sounds like the best explanation for that fragment in the back of - the outside of his skull - is just as the forensic experts thought: it's probably a shrapnel fragment.
REX: Interesting. So, so now, the second shot, around Zapruder frame 204 is something you call "The Rogue Shot," because it doesn't match the Book Depository or the Knoll as the source of the shot. And therefore -
DON: Well, actually -
REX: I'm sorry, go ahead.
DON: Yeah, it does match to the Book Depository -
REX: Oh, it does?
DON: The problem is that it's too close in time to the earlier shot to come from Oswald's rifle. When the FBI tested Oswald's rifle, the fastest they could cycle it - and this is both the FBI and the Army Weapons Testing branch - three different guys from each organization tried that rifle, and the fastest guy who could rotate - you know, cycle the gun - and fire two shots was two and a quarter seconds, and those shots are spaced by only a little over one and a fraction second. So, it's like, one of them was one point six seconds. So, it's too close to the earlier shot, so they can't both have come from the same Mannlicher-Carcano rifle.
REX: Sure. By the way, when you say Book Depository shots, I'm curious as to how accurate the analysis of the source of the shots were. In other words, are we talking sniper's nest, or somewhere in the general vicinity of the Book Depository? The sixth floor?
DON: Yeah, not, not real accurate at all. Because, the most important factor that determines the origin of the gunshot, the sound - the echo pattern - is going to arrive at the motorcycle is the position of the motorcycle relative to the buildings, and not to where the shooter was. If you go - the only one that was analyzed closely of all the five shots, the only one that was analyzed closely to try to determine the origin was the Grassy Knoll shot.
Now that - each of the other shots - I'm going to back a little bit - when the acoustics experts did their analysis - remember, they had these 72 test shot patterns - and they had 36 microphone locations at 18 foot separations - in theory, that motorcycle's probably not going to be exactly where that motorcycle is. It's probably gonna be somewhere in between 'em. And, as a consequence, they got multiple matches.
Now, in all but one instance, those multiple matches were to adjacent microphones. But, furthermore, in several of those instances, there were shots that matched - for example, that very first pattern had four matches. One of those was a shot from the Grassy Knoll.
REX: Heh, interesting.
DON: But it matched to a lesser degree than the shot that was - the test shot from the Book Depository. So, you really can't pinpoint exactly where the shot came from based on the original BBN analysis. The only one that actually pinpointed the origin of the gunshots - of any of the shots - was when Weiss and Aschkenasy studied that shot from the Grassy Knoll - that fourth shot.
REX: I see, so -
DON: And it was very much in line with that FBI argument that said, "well, hell. How do we know that there isn't a shot - a backfire, or a large firecracker - which could have been anywhere in the vicinity?" That, that's a valid argument, and that's why Weiss and Aschkenasy had to pinpoint it down to within a foot or two of where the actual shooter was.
REX: I see, but, so for the shots that are, um, supposedly Book Depository shots, they certainly could have been from a different part of the Book Depository, or something possibly like even a Dal-Tex building? Is that far off?
DON: Yeah, exactly. We presume that they're from the Book Depository because the eyewitnesses look up and saw a guy with a gun shooting at the President from that window, so it's - presumably some of these are really some of the assassination gunfire, well then some of them have to be -
REX: Sure, but if you have -
DON: - shots from the Book Depository. But at least one, that second one that I call "The Rogue Shot" that one is the one that is the very least likely that couldn't have come from the same rifle. It's gotta be from somewhere else.
REX: Now, this shot is possibly one that hit James Tague? The second shot?
DON: Right, we don't know if the first one - the one that hit the street is probably the best guess for one that struck the curb, then bounced up and hit Tague, that's the one we think hit the street. But the second one, we really don't know where it went.
REX: I see.
DON: We don't know where it came from.
REX: OK. Now, on the third shot, this is one where I suppose you're controversial on all sides of the issue, because you have written that this shot is a candidate for a "single bullet" shot, although not a "magic bullet" shot. Do you want to explain that?
DON: Right, sure. The, the - I know that the Single Bullet Theory is very controversial, and I started out thinking, boy, that's a bullshit - excuse my tourets - theory. But when I began to put things together and realize the acoustical evidence does show it coming from the rear, and that - and I have actually calculated the angles - the angles calculated by the House Select Committee, by the way, are wrong. But when you do calculate the angles, there's enough slop, there's enough looseness in there that yeah, you could have had a single shot go through Kennedy and hit Connally.
One of the more convincing things is the fact that the bullet that went through Kennedy was - well, I'm sorry - by the time it hit Connally, it was tumbling. The bullet wound in Connally is an elongated wound, which is not the kind of wound that you would get if the bullet hit straight on.
REX: Well, I wanted to take issue with that, because was Connally turned at that point? I mean, my understanding of the measurement of that wound is elongated roughly to the same extent as the purported entry wound in Kennedy's head. You know, 1.5 millimeters by .6 or .8 - clearly that bullet wasn't tumbling.
DON: Yeah, I don't know of any measurement that hit Kennedy in the head that was 1.5 centimeters long.
REX: The head injury wound, as measured at the autopsy.
DON: Well, I don't - he had an enormous wound at the top of his head, of course. So, I'm not sure what bullet wound at the top of the head you're referring to.
REX: The entry wound is the one. Which, in itself -
DON: Well -
REX: - pieced together.
DON: Right, there you go. Exactly. Now we're talking. We're talking about something that was reconstructed.
DON: It wasn't really measured.
REX: But wouldn't Connally being turned possibly account for that? Or not?
DON: I don't see that he could - how just being turned, coming from the Book Depository - 'course, that's one of the big issues. That's why there's slop in this analysis because we don't know exactly what their posture was.
REX: OK. Alright, on the - the fourth shot is Z-312, which is the infamous shot from the Grassy Knoll in this analysis. And then the fifth one comes just under a second later, also apparently from the Book Depository or that vicinity. Any thoughts on where that one went?
DON: Yeah, I'm pretty sure that's the one that went over the limo and hit the grass over by the manhole cover over near by where Tague had been standing. This is the one that the witnesses said the police came over and someone dug a - claimed that they'd taken a bullet out of the grass.
In fact, it was the day after, on Saturday, that Carl Day, the forensic bureau fellow for the Dallas Police Department went out with a tape measure and measured the distance from the Book Depository to that spot. When reporters asked him what he was doing he said, "well, this is a place where we recovered a bullet."
So, I always figured that was the bullet they dug out of the grass, and was probably Commission Exhibit 399.
REX: OK. One thing that's occurred to me is a lot of the - you know, many people were interviewed about how many shots they heard in Dealey Plaza, and you get "three" an awful lot. Of course, many of the people who were asked knew what the right answer was - a lot of them were official people, but there were certainly other people who weren't - and most people didn't say "five," and I'm curious if you have any thoughts on the earwitnesses?
DON: (laughs) Well, one of the problems was going to be - with two of those shots so close together - I guess one of the problems is - you know, they did a reconstruction, a sort of aural reconstruction in Dealey Plaza years later, and one of my complaints about that is what they did was - the acoustical experts - they went out and they stood at different spots, because it was noticed that the people who were standing near the Book Depository were the ones who generally thought shots came from the Book Depository. People standing out further west, out close to the Grassy Knoll, were the ones who thought the shots came from the Grassy Knoll.
Now, the problem is, you know, it's an entirely different problem if you're standing there and listening, and you know somebody's going to fire a shot, and you're standing there and listening, and trying to figure out where its coming from, as to someone who's completely taken by surprise. Doesn't know there's going to be shot. Then, if you have those shots which are fired in close succession - which in this case, you've got - and I say three shots close together, and then you've got two shots close together - a split second apart. Depending on where you're standing in Dealey Plaza, those two are going to sound pretty darn close.
REX: Particularly with the echo patterns, I would imagine.
DON: Yeah, or farther apart, then you've got the echos on top.
DON: The interesting thing is that they found on that - when they did that reconstruction - the original purpose of that reconstruction was the claim that they had made that maybe it was the echos that had confounded the witnesses. They were trying to explain why was it that so many witnesses thought it came from the Grassy Knoll - which, as you know, Josiah Thompson had shown, it was the majority of the witnesses - and the argument was, "well, must have been confused by echos."
And then, when they did the test, they found that there was no confusion. It didn't matter where you stood in Dealey Plaza - a gunshot from the Grassy Knoll sounded like it came from the Grassy Knoll, and a shot from the Book Depository sounded like it came from the Book Depository.
REX: Hmm... interesting. Don, it's been a pleasure talking with you. Thanks for taking the time with us.
DON: Sure thing.
TYLER: Keeping up with the tradition of having the final word, I just wanted to extend, on behalf of the entire Mary Ferrell Foundation, our thanks to Don for taking time to sit down with us. I hope you enjoyed, and we'll see you in the not too distant future, next time on Unredacted.