The arrest came just weeks after a Richmond, Virginia, FBI field office internal memo was leaked and identified "radical-traditionalist Catholic[s]" as potential "racially or ethnically motivated violent extremists," and relied on data from the SPLC.

That memo has since been rescinded, but Republican lawmakers from both chambers have questioned Justice Department and FBI leadership on its origination and application.

SPLC SLAMMED FOR BLAMING POLICE AFTER STAFFER'S DOMESTIC TERRORISM ARREST

"The SPLC has essentially converted to SPL-Qaeda. They gaslight violence against conservatives while masquerading as an authority on civil rights," Gaetz told FOX News Digital in a statement.

"Why does the FBI rely on a group who now has definitive ties to staff coordinating and participating in activities that local law enforcement categorizes as domestic terrorism? This is yet again another area of investigation that House Republicans must look into when conducting oversight of these weaponized agencies," Gaetz said.

The FBI would not comment specifically on their policy of relying on the SPLC, but did say, "while our standard practice is to not comment on specific intelligence products, this particular field office product – disseminated only within the FBI – regarding racially or ethnically motivated violent extremism does not meet the exacting standards of the FBI."

FBI UNDER PRESSURE AS SENATE, HOUSE MEMBERS SEEK ANSWERS FOR ’DISCRIMINATORY' ANTI-CATHOLIC MEMO

JORDAN DEMANDS ANSWERS FROM WRAY AFTER LEAKED FBI MEMO SUGGESTS AGENCY MAY BE TARGETING CATHOLICS

"Upon learning of the document, FBI Headquarters quickly began taking action to remove the document from FBI systems and conduct a review of the basis for the document," the FBI said.

"The FBI is committed to sound analytic tradecraft and to investigating and preventing acts of violence and other crimes while upholding the constitutional rights of all Americans and will never conduct investigative activities or open an investigation based solely on First Amendment protected activity," the agency said.

Last month, House Judiciary Chairman Jim Jordan, R-Ohio, sent a letter to FBI Director Christopher Wray demanding answers on the memo noting that the SPLC "identifies the broad term ‘Christian identity’ as a hate group — a term that could arguably encompass millions of Americans with sincerely held religious beliefs."

"The fact that the FBI would blindly accept and regurgitate the SPLC’s spin is highly concerning and undercuts the FBI’s assertion that it is unbiased and politically neutral," Jordan wrote last month.

Fox News Digital's Emma Colton contributed to this report.