Chele Farley, the Republican nominee for the U.S. Senate seat held by incumbent Democrat Sen. Kirsten Gillibrand (N.Y.), slammed her rival over ties the senator's father has to a group charged with sex trafficking.

Farley attacked Gillibrand for claiming ignorance about the existence of Nxivm and her father ties to the group, a multi-level marketing and self-help group that has been accused of sex trafficking and financial impropriety, according to the New York Post.

"For Kirsten Gillibrand, the self-proclaimed #MeToo Senator, to claim ignorance about a notorious sex-slave cult, in her own backyard, is simply hard to believe," Farley said.

Gillibrand's father, Doug Rutnik, was hired by Nxivm as a lobbyist in 2004.

Nxivm's leader, Keith Raniere, was arrested in Mexico on Monday by the FBI and charged with sex trafficking. The 57-year-old Raniere founded Nxivm, which bills itself as a "community guided by humanitarian principles that seek to empower people and answer important questions about what it means to be human," in 1998. Nxivm is accused of operating a pyramid scheme that foxed its members out of thousands of dollars.

In addition to the alleged financial impropriety, Raniere is accused of setting up a secret sorority within the organization to exploit female members. The FBI alleges the group recruited women to serve as sex "slaves" for Raniere and other high-ranking members of Nxivm. Apart from being sexually exploited, the women were also branded with Raniere's initials and forced to eat low-calorie diets to fit his preference for "thin women."

Nxivm is alleged to have dozens of chapters across the globe, with members ranging from Hollywood celebrities to the son of a former Mexican president. Former members of the group have described it as a "cult" centered around Raniere.

Rutnik, who was paid $25,000 a month, worked for the organization for a fourth-month span before parting ways.

A source originally told Page Six that Rutnik was "falsely sued" by Nxivm when he attempted to distance himself from the group. Rutnik eventually settled for $100,000.

A spokesman for the New York senator said she had no connection to the group and had only recently heard of them through extensive media coverage. The spokesman also expressed that Gillibrand was "glad" law enforcement authorities were taking proper action against the alleged wrongdoing.

"Senator Gillibrand had never heard of this group until she recently read about them in the newspaper," the spokesman said. "She is glad that federal and state prosecutors have taken action in this case."