Julie Holowach, 63, was killed by a great white shark in a fatal attack in the US state of Maine.
The woman was swimming near Bailey Island on Monday when she was attacked.
This is the second shark attack in Maine. The species is not common in the region because of its cooler waters.
Ms Holowach was swimming just 18 metres offshore with her daughter near Mackerel Cove when she was attacked, according to the Portland Press Herald. The younger woman was uninjured.
A neighbour, Tom Whyte, told the newspaper he had seen the attack from his office overlooking the cove.
“You could hear her giggling and laughing,” Mr Whyte said. “All of a sudden Julie just started screaming for help.
“And all of a sudden Julie went under. It looked like she was pulled under.”
He said Ms Holowach’s daughter had started swimming towards her.
Two kayakers helped Ms Holowach get to shore after the attack.
An ambulance was also on hand to help at the scene, but she was later pronounced dead.
A tooth fragment from the scene confirmed she had been attacked by a great white shark, a local official said.
Ms Holowach was reportedly wearing a wet suit and her daughter was not, fuelling speculation locally that the shark may have mistaken the older woman for a seal.
She recently retired as a fashion executive from New York.
Great whites have been sighted in recent summers in Maine, where many seals swim in local waters.
The only previous such attack recorded in Maine waters happened in 2010 and involved a scuba diver fending off a porbeagle shark, according to the Press Herald report. The diver was not injured.