“She ultimately stranded and was further harassed by a crowd of people on the beach where she later died before rescuers could arrive on scene,” the network said.
Officials have obtained footage of the harassment in Texas that may help in identifying the people involved, NOAA said.
The Marine Mammal Protection Act prohibits the harassing, harming, killing or feeding of wild dolphins.
Harassing, harming, killing or feeding wild dolphins is punishable by up to $100,000 in fines and up to 1 year in jail per violation, the agency said.
The animal was apparently in a begging position for feeding when it was attacked while still alive. She appeared to have died from the trauma, NOAA said in a statement.
“Begging is not a natural behavior for dolphins and is frequently associated with illegal feeding. People can help prevent future harm to wild dolphins by not feeding or attempting to feed them,” it said.
The agency — whose mission is stewardship of ocean resources and habitats — advised people to avoid interacting with stranded marine animals because they may be sick or injured.
Pushing animals back into the water delays the animal getting the help it needs and may result in re-stranding in worse condition, it said.
CNN’s Michelle Watson and Rebekah Riess contributed to this report.