Robert F. Kennedy Jr.'s cousin, Caroline Kennedy, urged lawmakers to reject the nomination for the controversial political figure and conspiracy theorist to be named as the United States Secretary of Health and Human Services.
She also alleged that he used to "show off" by killing animals using a blender.
As reported by ABC News, Kennedy issued the letter on Tuesday ahead of his confirmation hearing for the position on Wednesday, describing her cousin as a "predator" unfit for the role of Health Secretary.
"I have known Bobby my whole life; we grew up together," she wrote. "It's no surprise that he keeps birds of prey as pets because he himself is a predator."
She also said that RFK Jr. battled with drug addiction, which led to increasingly disturbing behavior.
"His basement, his garage, and his dorm room were the centers of the action where drugs were available, and he enjoyed showing off how he put baby chickens and mice in the blender to feed his hawks. It was often a perverse scene of despair and violence," she continued.
Kennedy alleged that RFK Jr., despite his anti-vaccination activism, had his children vaccinated and "preys on the desperation of parents of sick children."
She wrote that RFK Jr. continues to profit off a lawsuit against pharmaceutical company Merk over Garadasil, a vaccine that can help prevent cervical cancer. (PBS reports that he made $850,000 from the deal last year.)
"He is willing to enrich himself by denying access to a vaccine that can prevent almost all forms of cervical cancer and which has been safely administered to millions of boys and girls," Kennedy wrote.
Her son, Jack Schlossberg, shared a video of his mom reading out the letter on Instagram, expressing his support for Kennedy's comments.
RFK Jr. ran for president last year but pulled out of the race to endorse President Donald Trump in August after appealing to both Trump and Kamala Harris for a cabinet position.
He has since drummed up support with the slogan "Make America Healthy Again" while voicing his desire to end the restrictions on sales of raw milk and promoting vaccine misinformation.