A bright blue sky stretched across Florida's Watersound Beach, a private stretch of sand in the Panhandle accessible only to one nearby community. It was June 7, 2024, and scores of sunbathers splayed on towels or under beach tents. The two sandbars off its shore, at 30 and 60 yards out, were dotted with bodysurfers and swimmers.

Among them were Elisabeth Foley, on vacation from Virginia with her husband, Ryan Foley, and their three children-Dominick, 13; Lyla, 15; and Laurel, 17-who splashed happily in the shallow waters of the first sandbar.

Keith Harrison, a neuropathologist from Alabama, was also at the first sandbar with his two sons, ages 9 and 12, bodysurfing the short waves. They were at the tail end of a weeklong family trip, and for the first few days, the water had been a little murky. But on Friday, it was crystalline, and they planned to enjoy it.

Then came the screams.

Dr. Harrison at first thought the screams were from kids playing. But as he turned toward the commotion, he saw a plume of blood spreading in the water. He left his kids with his wife and ran toward it. As he arrived, he saw Elisabeth Foley emerging from the water. Her hand and half of her left forearm were missing. Flesh from her buttocks hung in ribbons, and blood poured from her pelvis. Her three children wailed around her. Her husband held her up.

A shadowy figure lurked just behind them in the water, keeping strangely still in the crimson-tinged tide. A bull shark. Dr. Harrison grabbed Elisabeth from her husband and started carrying her toward shore as Ryan wrangled the kids. As he clamped his hand around Elisabeth's left brachial artery-the vessel that supplies blood to the arm-a word sprang into his mind: horrific.

Rylee Smith, Bailey Massa and Abby Juedemann had spent all morning at Watersound Beach, swimming and sunbathing. The three of them, plus a fourth friend, had driven all night from Columbia, Missouri, for a girls' beach weekend.