What did David Swain do? Harrowing details of his wife Shelley Tyre's death on Dateline explored 

The heartbreaking and unsolved loss of Shelley Tyre during a scuba dive with her spouse, David Swain, has been a topic of speculation and sorrow for over 20 years now. A beloved school manager, Shelley was found dead on the seabed near Tortola in 1999.

Since Shelley Tyre was a seasoned diver, her sudden passing sparked a lot of questions and suspicions. The tragedy has led to accusations, legal battles, and a never-ending debate about whether it was just a terrible mishap or something much more sinister, like a planned murder.

Dateline: Unforgettable investigates this story, piecing together the moments that still haunt the lives of those who were involved.

---

What happened to Shelley Tyre during the fateful dive?

On March 12, 1999, a terrible event took place during what was supposed to be a perfect vacation. Tyre and Swain were enjoying their time at a well-known diving spot, the Twin Wrecks, with another couple. They were both diving enthusiasts and had planned to explore the underwater beauty together. As they dived in, they decided to split up so that Swain could take photos of the marine life and Shelley Tyre could count the fish.

But when Swain came up by himself, he didn’t seem too worried at first. It was only when their friend Christian Thwaites found Tyre’s lifeless body down below that things took a dark turn. Her scuba gear was all messed up—her mask strap was loose, the snorkel mouthpiece was nowhere to be seen, and one of her fins was buried in the sand. This made people wonder if her death was just a terrible accident or if something more sinister had happened.

When Shelley Tyre’s parents, Richard and Lisa Tyre, looked into it, they found some things about Swain’s story that just didn’t add up. They had a feeling that maybe it wasn’t an accident after all. So, in 2002, they decided to take him to court. They claimed that he had messed with Tyre’s gear on purpose to get rid of her. The court actually agreed with them.

They said that Swain had to pay $3.5 million because of how suspicious the situation was and because he got a lot of money, about $600,000, from Shelley Tyre’s will. It was like they thought he had something to do with her tragic death. It was a sad and shocking end to what should have been an amazing trip.

---

David Swain’s legal battle, conviction, and controversy

The civil ruling led to Swain facing criminal charges. Back in 2009, he found himself in hot water in Tortola, accused of murder. The prosecution claimed that he had reasons to want his wife, Shelley Tyre, out of the picture—like money woes and a prenup that didn't leave him much if they split up. Plus, they threw in the spicy detail that he had feelings for someone else.

During the trial, some love letters from Swain to this other woman came to light. He had called her his "soulmate," which definitely didn't look good for him. The prosecution tried to show that he was a guy who would do anything, including something terrible, to get out of his marriage and maybe get cash in that process somehow.

And then there was the state of Shelley Tyre's diving gear. It was all messed up like someone had ripped the mask strap off with a lot of force. This seemed to back up their whole "Swain did it" story.

Prosecutor Terrance Williams laid it all out for the judge and jury:

“This man’s dreams came true after his wife’s death.”

Swain's defense team went to bat for him, pointing out that he's never been in trouble for hurting anyone before and questioning when Shelley Tyre passed. His kids took the stand to say what a good person their dad is, and his lawyers said his calmness during all this was because of some trauma when he was young.

But even with all that, a jury still found him guilty of murder, and he got 25 years in the slammer. It wasn't until 2011 that a higher court asked them to hold up because of some mistakes made during the trial and the whole thing happening so long ago. They tossed out the guilty verdict.

---

If you want to see the interviews and scenes from the courtroom, watch Dateline: Unforgettable on Peacock or the Oxygen app.

More Dateline cases: Rob Limon, Tara Fitzgerald, and Linda Collins