Wellfleet Police Lt Michael Hurley confirmed the victim, a man in his mid-20s, died of his injuries following the attack, the first fatal shark incident in MA since 1936.
The shark struck in waters around 300 yards off Newcomb Hollow Beach in Wellfleet at 2:25pm local time (7.:25pm GMT) on Saturday.
Procopio said in an e-mail to the Globe that the victim's family has been notified of his death, but he did not release the man's name. The Cape Cod District Attorney's office and the Massachusetts State Police are both investigating, Hurley said.
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Seashore rangers and police performed CPR on the victim after he was pulled from the water, the Cape Cod Times reported. "The sign advises to avoid swimming near seals, to swim close to shore in waist deep water, and to swim or surf in groups", said the CBS affiliate.
Witness Joe Booth described a harrowing scene at the Wellfleet beach when the incident occurred.More news: Liverpool hold off Spurs to maintain flawless start
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The legislators offered help to all Cape Cod towns in responding to risks posed by shark activity.
The incident happened at Newcomb Hollow Beach around lunchtime on Saturday (US time).
"We are witnessing sharks feeding aggressively in shockingly shallow water on an nearly daily basis over this past August", he wrote.
Mr Booth said the attack victim and his friend were boogie-boarding when the attack happened.
'It was like right out of that movie Jaws. Booth said he saw the man aggressively kick something behind him and a flicker of a tail from the water.
On 15 August, the state saw its first attack since 2012 when a NY man was severely injured off Truro, also on Cape Cod. "This has turned into Amity Island real quick out here", he admitted to WBUR. He's still recovering from his puncture wounds in a Boston hospital.