Former independent presidential candidate Robert F. Kennedy Jr. confirmed over the weekend that he is under investigation for “collecting a whale specimen 20 years ago.”

“Right after I endorsed President Trump, I received a letter from the 'National Marine Fisheries Institute' saying that they were investigating me for collecting a whale specimen 20 years ago," Kennedy said Saturday at an Arizona campaign event for former President Trump in a clip published by NBC News.

"This is all about the weaponization of our government against political opponents of the party in power," Kennedy added later.

Kennedy seemed to be referring to the National Marine Fisheries Service (NMFS), a part of the National Oceanic and Atmospheric Administration (NOAA) that is responsible for marine fisheries.

‘It is long standing NOAA practice not to comment on open investigations,” NMFS Director of Public Affairs Kate Silverstein said in an email to The Hill.

In 2012, Kennedy’s daughter Kick told Town & Country Magazine that her father cut the head off a whale that had washed up on the shore in Hyannis Port, Mass., when she was a child. The interview gained traction again recently after Robert F. Kennedy Jr. ended his campaign and endorsed Trump.

An environmental advocacy group last month called for Kennedy to be investigated over the incident. The Center for Biological Diversity Action Fund said in a letter to NOAA that it is “illegal to possess any part of an animal, dead or alive” under the Marine Mammal Protection Act and Endangered Species Act and that NOAA should open an investigation.

In late August, Kennedy said he was suspending his campaign and backing Trump. 

“In my heart, I no longer believe that I have a realistic path to electoral victory in the face of this relentless, systematic censorship and media control,” Kennedy said at the time. “So I cannot in good conscience ask my staff and volunteers to keep working their long hours, or ask my donor to keep giving when I cannot honestly tell them that I have a real path to the White House.”

The Hill has reached out to the Kennedy's team.

Matt Corridoni, a spokesperson with the Democratic National Committee (DNC), directed The Hill to a Monday press release from the committee.

“At a recent Trump campaign event, newly-minted MAGA surrogate RFK Jr. told an audience that he was being investigated by the National Marine Fisheries Service for illegally decapitating a whale carcass with a chainsaw,” the DNC said in the release. “This story once again prompted a flurry of negative and embarrassing headlines about RFK Jr."

This story was updated at 3:54 p.m.