(Warning/disclaimer - This is going to be loooong.)
I too was very interested in seeing the "Dateline" piece Friday night. And rather than answering things post-by-post, I thought I'd take a run at the entire body of evidence and see what it might say, now that many of us have had a chance to see it presented and heard some of David's own words.
I also want to remind people of the two things I do. One is that I'm the Forensic Consultant for the Los Angeles County Coroner when there's a scuba fatality. So what I'm about to write are some of the thoughts I'd have or questions I'd raise if I was looking at the case from that perspective.
The second thing I want to remind you of is that I've also had a career as a journalist, mostly with PBS (KCET-TV) here in L.A., but also with KABC-TV, plus some radio stations, and I still do work for LACityView35.
From a journalistic standpoint, I thought the NBC piece was quite fair and balanced. All they seemed to do, to my eye/ear, was really present all the different facts and facets of the case. If you feel David didn't do it, I think you could walk away feeling the NBC program supported that view. If you feel David did do it, I think you could walk away feeling that view was supported as well.
But they did make some interesting editing choices. I found it especially intriguing that they chose to close with a powerful quote from Betsy Dake: "Prison means that there are no other facts, there are no other explanations. Prison means that there is no reasonable doubt . . . When I look at the possibilities, there's a ton of reasonable doubt." Interesting choice as the closing in an otherwise balanced piece.
I have to confess that theres one thing that bothers me a bit in some of the posts we've made here as well as in the program. And thats the overuse (IMHO) of the term "reasonable doubt." To my mind, there's "doubt" and there's "reasonable doubt." In other words, I could offer some other scenario (like with the fin-in-the-sand) to induce doubt but that doesn't make it "reasonable".
Possible? Maybe. Plausible. Not so much.
Theres a very useful thing I learned long ago thats called Occam's Razor. Its a corollary that simply says, when all else is equal, if you have two hypotheses, the one that requires the least twisting and turning of thought is probably the most likely correct. In other words, the simpler explanation is more likely to be true than the more convoluted one.
When thinking of this, Im reminded of Rose Mary Woods, secretary to President Richard Nixon during the Watergate crisis. You may recall that there was a question of an 18-minute gap in the secretly-recorded White House tapes. It was widely presumed that the gap was deliberately erased, most likely by Nixon, and that it was to cover-up damaging evidence of his involvement with either Watergate or the cover-up.
Then along comes Ms. Woods with her explanation thats now known as The Rose Mary Woods Stretch. She explained that it was she who had accidentally erased that portion of the tape one day as she answered the phone. She reached to her left for the phone while stretching her foot in the exact opposite direction and accidentally hitting the erase button on the Dictaphone, obliterating 18 minutes of tape.
She even showed reporters what she meant in this famous photo:
Applying the principles of Occams Razor in case of the Nixon tapes, your choices are (1) Ms. Woods' convolutions and contortions, or (2) that someone - likely Nixon - deliberately erased the damning portions of the tapes. The simpler answer is a more straightforward explanation and, according to Occam, more likely to be true.
And if you ever try to duplicate what Woods supposedly did, its not how youd normally move when answering a phone. Possible? Yes. Plausible? No.
In the Swain case, keep those principles in mind. Also remember that we need to look at the totality of the evidence. You can't just cherry-pick the facts. It doesn't mean a hypothesis has to answer everything but the more answers a hypothesis can provide, the stronger a candidate for the truth it likely is.
Also remember that a lot of times you deal with a sequence of events, like cause-and-effect. If A happened, then B would happen. If B happened, then we'd see C. And so on. So at some point, if you don't see C, then it can't be A.
Also realize that some times what you do is assemble every single plausible and implausible scenario. And then you start testing them. You knock them out one-by-one because the evidence doesn't support the theory. In the end, if you are left with one scenario that you can't disprove, there's a good chance that that's what happened.
There are some other unusual and specific facts we have to consider in devising scenarios:
1. Mask is off with strap pin dislodged.
2. Snorkel is off of mask strap and missing lower portion.
3. Fin is found tip-first in the sand.
4. Heel strap on fin is pulled back and underneath.
In this case, we start with the fact that Shelley Tyre is found drowned underwater. The regulator is out of her mouth but there's still air in her tank. So the first things we start to ask is, Why would this happen? (And we can look at this in the absence of medical evidence, though we now know that the ruling is drowning, which really doesn't tell us much. We still want to know "Why.")
Apparently, there was no equipment malfunction. I know there are some questions about the testing of the gear. But what will happen to gear that just sits around is it may corrode and get worse than on the day of the accident. But it won't get better. So even if the gear wasn't tested back in 1999, my understanding is that once it was tested, it worked. So we rule out equipment malfunction.
There's been a lot of talk about Shelley panicking. Let's look at that. I don't give a lot of weight to the notations in her logbook. The woman had 350 dives under her belt. The conditions that day sounded pretty benign. What was the trigger that would have caused her to panic? Possible? Yes, although saying that panic can strike any diver at any time is a bit of an overstatement IMHO. Plausible? I'm not convinced. Heres why.
In a panic situation, a diver most likely bolts to the surface. They may not make it all the way up but the panic response in a diver is the classic fight-or-flight and they shoot up looking for air and the "safety" of the surface.
If Shelley panicked, could a panic ascent explain everything? It certainly would explain the reg-out-of-mouth. It might also explain the mask as she could have ripped it off in a panicked state. But it doesn't explain how the snorkel would have come off the mask let alone apart, and it certainly wouldn't explain the fin-in-the-sand.
To me, fin-in-the-sand is a big one. As I mentioned in a previous post, expert Bill Oliver tested the fin and found that when they were dropped, they fell to the bottom foot-pocket first, not tip first. (This makes sense as the foot pocket is heaver than the tip and, as it falls, the heavy end rotates down to become the first thing to hit bottom.) The only way Bill could get the fins in the sand tip-first was to jam them in by hand.
This experiment was repeated for the NBC show by Keith Royle. He said: I went down in the same area and tried to do the same thing myself with the fin on, and it was impossible. The only way I could actually get it to stick in the sand was physically, with my hands, putting it into the sand."
For this scenario to work, you'd have to argue that a panicking diver first pulled her fin strap under the heel, then took off her fin, jammed it in to the sand tip-first, and THEN bolted for the surface??? Occam's Razor: Too convoluted, and doesn't explain the snorkel.
I just dont think the totality of the physical evidence supports any theory that Shelley panicked and bolted.
Are there other accidental ways she could have dislodged the reg from her mouth AND caused the other things as well? She could have gotten the reg lodged/stuck in a piece of the wreck but there's no evidence to support that. She could have lost the reg from her mouth and a current swept the reg out of her grasp but there's no evidence to support that. She could have had an uncontrollable coughing spell which caused the drowning but that wouldn't explain the mask/snorkel/fin.
I don't think there's an accidental scenario that fits the totality of the physical evidence.
So if it wasn't accidental, and assuming she didn't commit suicide (also wouldn't explain the mask/snorkel/fin), could it have been deliberate by someone else? because those are really our only two choices: Accident or Deliberate. If you rule out Accident, you have to look at Deliberate. Remember you're going to need Means and Opportunity, and then Motive for it to be murder.
Anyone underwater had the Means to do her in by cutting off or eliminating her air supply. Could it have been someone unknown? Well, there's no evidence or testimony of any other boat in the immediate area so we can probably rule out some unknown third party swimming up to her and killing her.
But we do know of TWO people who had Means and Opportunity and that would have been Swain and Thwaites. Let's look at Thwaites first.
There's been talk of Shelley's air consumption and the assumption that whatever went wrong happened about 8 minutes into the dive. But others contend that Shelley had much better air consumption than is being presumed, which would have pushed the timeline back. So let's say that maybe this happened 16 minutes into the dive. And if you really want to be generous, give her phenomenally low air consumption and make it 20 minutes in to the dive.
I don't recall why, but my impression is that Swain did about a 30-minute dive. Thwaites wasn't going in until Swain was back on the boat. Let's assume it took Thwaites 5 minutes after Swain re-boarded the boat to gear up and do down. Give him another 2 minutes to get to the bottom (80-ish feet), maybe another 1 minute to get to the fin, and then 1 more minute to get to the wreck and Shelley.
That's 39 minutes. No matter whose timeline you use (8 minutes, 16 minutes, or 20 minutes), whatever happened to Shelley had to have happened before Thwaites got to her. That eliminates Thwaites as a suspect.
So if we've eliminated Accidental and accept that it was Deliberate, and if we've eliminated an unknown third party and Thwaites, that only leaves one person with Opportunity: Swain. That doesn't mean he did it. But it does mean we should look at it this from that perspective and test that scenario.
For those of you that know David or have formed an opinion one way or the other, you need to try to set that aside for the moment and just think of this as two unknown divers. Without taking into account character or motive, you have to dispassionately look at whether or not this scenario is possible &/or plausible based on the evidence, not based on what you may feel about David personally.
If he took away her air, how could he do it? I saw on NBC the video the prosecution produced and while it might be possible, I'm not so sure it's plausible. For one, I think it fails Occam's Razor as it's a bit complicated.
It takes about 3-4 turns of the knob to shut down someones air. You rotate your wrist in roughly half-turns. So it's really 6-8 wrist rotations to turn off someone's air. In the time it's taking you to turn it off, they've got time to react and perhaps fight you off. They'd certainly know something was amiss and there's a chance they could get away. But there's an easier and simpler way.
Stay behind the person, wait for them to exhale and when you see the bubbles stop, yank the reg from their mouth. This not only catches them by surprise (and induces anxiety) but it also means they have less air in their lungs and will become air-starved more quickly.
By approaching from behind, you can also clamp you knees around the tank which will make it virtually impossible for the other diver to dislodge you. (Try it in a pool sometime, minus the out-of-air part.) On top of that, given where the body was found, it's possible to have used the wreck for leverage to hold Shelley down.
(Part 2 follows as a separate post.)
