(NewsNation) — An environmental group is calling on the National Oceanic and Atmospheric Administration to investigate a recent report about Robert F. Kennedy Jr. cutting the head off a dead whale in Massachusetts and then taking it to New York.

Kick Kennedy, the daughter of RFK Jr., recounted the story in an interview with Town & Country magazine in 2012. When Kick Kennedy was six, “word got out” about a dead whale that washed up on Squaw Island in Hyannis Port, according to Town & Country.

RFK Jr., who the article notes liked to study animal skulls and skeletons, ran down to the beach with a chainsaw and cut off the whale’s head. He then “bungee-corded it” to the roof of the family minivan and went back to Mount Kisco, New York, the news outlet wrote.

“Every time we accelerated on the highway, whale juice would pour into the windows of the car, and it was the rankest thing on the planet,” Kick Kennedy recalled to Town & Country. “We all had plastic bags over our heads with mouth holes cut out, and people on the highway were giving us the finger, but that was just normal day-to-day stuff for us.”

Although the incident seemed “normal” to Kick Kennedy at the time, the Center for Biological Diversity Action Fund wrote in a letter to NOAA’s Office of Law Enforcement that it’s “illegal to possess any part of an animal, dead or alive, protected under either law.”

RFK Jr. transporting the whale skull to New York also potentially violated a law called the Lacey Act, which prohibits taking “any wildlife, dead or alive, that was collected in violation of any state, federal or international regulation or law” across state lines, the Center for Biological Diversity Action Fund said.

“RFK Jr. cutting off the head of a dead whale was both bizarre and illegal, and any serious environmental attorney would know better,” Brett Hartl, national political director at the Center for Biological Diversity Action Fund, said in a statement posted on the organization’s website.

“Kennedy may think that his name and privilege mean the rules don’t apply to him, but if he had a shred of integrity left he’d surrender this whale skull and any other illegally collected wildlife parts to the authorities. If he doesn’t, NOAA law enforcement should open an investigation and potentially bring charges against him.”

An investigation is needed to determine the species of marine mammal RFK Jr. unlawfully harvested, whether he still has the whale skull and if he has any other “unlawfully collected wildlife,” the organization said.

RFK Jr.’s press team did not respond to a request for comment.

The letter to NOAA comes just a few days after he announced the suspension of his independent presidential campaign and endorsement of Republican nominee Donald Trump. A spokesperson from the agency told NewsNation in an email that they received the note from the Center for Biological Diversity Action Fund and “will respond through the appropriate channels.”

While an “unverified anecdote” would usually not be enough evidence for such a probe, the Center for Biological Diversity Action Fund said in its letter that RFK Jr. has previously admitted to having “recklessly — and with no regard to legal requirements — taken other species of wildlife for his own personal benefit.”

RFK Jr. criticized for other incidents involving animals

One example of this “reckless” behavior, the Center for Biological Diversity Action Fund said in the letter, is another recently-publicized story about him retrieving a bear killed by a motorist and leaving it in New York’s Central Park.

Kennedy described the 2014 incident in a video posted to get ahead of the publication of a New Yorker article detailing it, which included a photo of the politician with his fingers in the bear’s bloodied mouth. In the picture, Kennedy’s left pant leg appears to have a bloodstain on it.

The incident, which Kennedy characterized as a prank, sparked a mystery that puzzled New York City residents for years.

“Apparently, without a salvage permit or legal tag, Kennedy took the bear cub because he wanted to skin it and eat the meat,” the Center for Biological Diversity Action Fund said. “But instead Kennedy said he dumped the bear cub in Central Park, creating a conservation mystery and wasting the resources of the New York Department of Conservation, which tried to determine how the bear cub ended up in Central Park.”

New York’s Department of Environmental Conservation, which enforces laws regarding wildlife, said in a statement that it closed its investigation after a forensic analysis concluded that the cub died from injuries consistent with a high-speed collision.

Possessing a bear without a tag or permit, or illegally disposing of a dead bear, are offenses punishable by fines of up to $250 in New York, but the department said charges cannot be brought for violations that occurred more than a year ago.

The Associated Press contributed to this report.