In the summer of 1916, leading scientists assured Americans that sharks in temperate waters were timid scavengers with jaws too weak to break human bone. Then, over 12 days in July, five people were attacked along the New Jersey coast and four of them died. This episode follows the attacks from the crowded resort beaches to a muddy inland creek, and shows how a heat wave and a polio epidemic had driven thousands of city dwellers into the water at exactly the wrong moment.

The first victim, 23-year-old Charles Vansant, bled to death on a hotel manager’s desk at Beach Haven, and officials still told the public there was no reason to stay out of the surf. Five days later Charles Bruder was killed at Spring Lake. On July 12 the terror moved to Matawan Creek, where a boy, his would-be rescuer, and a teenager were struck within the hour. Panic reached the White House, a huge shark hunt began, and the scientific establishment was forced into a public reversal.

• Bystanders at Beach Haven heard Vansant screaming and assumed he was calling to the dog he had been playing with in the surf.
• Sea captain Thomas Cottrell warned Matawan that he had seen a shark in the creek and was dismissed hours before Lester Stillwell, 11, was pulled under.
• Joseph Dunn, 14, survived a tug of war between the shark and his brother, becoming the only survivor of the five attacks.
• Taxidermist and lion tamer Michael Schleisser killed a 7.5-foot great white in Raritan Bay with a broken oar and found 15 pounds of human remains in its stomach.
• Scientists still debate whether one great white was responsible or whether a bull shark struck in the creek, where a full moon tide had more than doubled the salinity.