A tooth fragment was found at the scene of a fatal shark attack, confirming it was a Great White - just like in the classic film Jaws.
Mum Julie Dimperio Holowach was swimming in a wetsuit about 20 yards off the shore near Bailey Island, Maine, when she was likely mistaken for a seal, according to officials.
Frantic rescue attempts by kayakers saw the 63-year-old, from New York City, hauled out of the water but she was later pronounced dead by paramedics.
The incident, on Monday at around 3.20pm in Harpswell, is understood to be the first fatal shark attack ever recorded in the state's history.
New England shark expert Dr James Sulikowski, of Arizona State University, called it "surprising and shocking".
He also said sharks could be spreading north from Cape Cod as they look for food, with Maine known for its large seal population.
He added that measurements of a bite mark on a seal after an attack in nearby Phippsburg on Sunday suggest a shark at least 11 feet long.
Maine Marine Patrol confirmed the tooth fragment found was that of a Great White and have warned boaters and swimmers to avoid the area until further notice.
Maine Department of Marine Resources Commissioner Patrick Keliher said Gregory Skomal, senior scientist at Massachusetts Department of Marine Fisheries had confirmed the shark type after being provided with the evidence.
"It is the only confirmed fatality in Maine waters from a shark attack," said Commissioner Keliher.
"We urge swimmers and others recreating in or on the water in the Casco bay region, and in particular near Bailey Island to be aware of their surroundings and to avoid schools of fish or seals, which attract sharks," he added.
In the 1975 film Jaws, directed by Steven Spielberg, shark expert Matt Hooper (Richard Dreyfuss) is able to confirm a Great White is behind multiple fatalities off a tourist island in New England after finding a tooth in a sunken boat's hull.
Holowach, the former president of accessories brand Kipling, was swimming with her daughter at the time of the attack, who managed to swim back to shore unharmed.
