FIRST ON FOX: A gun rights group representing over 2 million members and activists is urging senators to grill Treasury Secretary Janet Yellen on alleged privacy violations committed by her department.

Yellen is set to testify before the Senate Banking, Housing and Urban Affairs Committee on Thursday. In a letter sent ahead of her testimony, Gun Owners of America (GOA) requests that committee lawmakers press the secretary on recent revelations that federal investigators asked banks to search and filter customer transactions for terms related to the firearms industry. 

"Congress cannot allow the federal government to continue establishing and expanding databases on guns and gun owners," wrote Aidan Johnston, director of Federal Affairs for GOA. "Whether it is the misuse of gun store records and financial data by the Department of Justice or firearm transaction data by the Department of the Treasury, data collection on guns and their lawful owners must be stopped."

Fox News Digital previously reported that the Treasury Department’s Office of Stakeholder Integration and Engagement in the Strategic Operations of the Financial Crimes Enforcement Network (FinCEN) distributed materials to financial institutions that outlined "typologies" of "various persons of interest" and provided the banks with "suggested search terms and Merchant Category Codes for identifying transactions on behalf of federal law enforcement."

'ALARMING' SURVEILLANCE: FEDS ASK BANKS TO SEARCH PRIVATE TRANSACTIONS FOR TERMS LIKE ‘MAGA,’ ‘TRUMP’

Treasury Secretary Janet Yellen

Treasury Secretary Janet Yellen testifies during the House Financial Services Committee hearing titled "The Annual Report of the Financial Stability Oversight Council," in the Rayburn Building in Washington, D.C., on Tuesday. Yellen is set to testify again to the Senate Banking Committee on Thursday. (Tom Williams/CQ-Roll Call, Inc via Getty Images)

Financial institutions were told to look for transactions with terms including "Trump" and "MAGA," as well as "Biden," "Kamala," "Antifa," "White Power," "Camp Auschwitz," "Proud B," "Storm, the," "Capitol," "Groyper Army," "Threepers," "boogaloo," "civil war," "last sons," "kill," "shoot," "gun," "death," "murder," "Pelosi," "Schumer" and "Pence."

FinCEN also provided banks with suggested terms and Merchant Category Codes for the firearms industry, including GOA partners like AR15.com, LLC; Browning Arms Company; Glock, Inc.; Sig Sauer, Inc.; Sturm, Ruger & Company, Inc.; and others. 

READ GUN OWNERS OF AMERICA'S LETTER HERE – APP USERS, CLICK HERE:

The purpose of flagging these transactions was to identify "potential active shooters" and "international terrorists," "domestic terrorists" or "homegrown violent extremists ('lone wolves')." 

The initial terms "MAGA" and "Trump" were revealed in a letter sent by House Judiciary Committee Chairman Jim Jordan, R-Ohio, to a former director of FinCEN, Fox News Digital first reported in January.

FEDS SUGGESTED BANKS SEARCH TRANSACTIONS FOR TERMS LIKE ‘BIDEN,’ ‘ANTIFA’ AND MORE AFTER JAN 6: SOURCES

Dick's storefront at Dulles Town Mall

Federal investigators told banks to search for transactions of certain sporting and firearm stores, like Dick's Sporting Goods. (Google )

The distribution of the search terms, including various members of the firearms industry, began in the final weeks of the Trump administration after Jan. 6, 2021.

A slide included in Jordan's letter, which was distributed to banks, detailed several parameters that transactions must meet before an individual was flagged as a "person of interest." Banks were told to look for transactions involving five or more distinct and different merchants or vendors involving the suggested terms; and an aggregate purchase totaling $2,500 or more using suggested MCC codes; and a number of transactions involving the provided terms greater than 50% of the total number of transactions by that customer; and an aggregate purchase amount at the MCC codes greater than 50% of total purchases by the customer.

The transactions had to meet all of those parameters before they were flagged to FinCEN investigators, meaning the vast majority of firearms transactions or transactions involving one of the suggested terms were not alerted to law enforcement

Even so, GOA raised concerns that the Treasury is "teaching financial institutions how to search financial data to find gun owners by flagging potential firearm transactions." 

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Rep. Jim Jordan gives a press conference

Rep. Jim Jordan, R-Ohio, chairman of the House Judiciary Committee. (Drew Angerer/Getty Images)

In his letter, Johnston pointed to testimony received by the House Judiciary Committee indicating that Bank of America provided the FBI "voluntarily and without any legal process" with a list of individuals who made firearms transactions in the Washington, D.C., metropolitan area using a Bank of America credit or debit card between Jan. 5 and Jan. 7, 2021, for the federal investigations into the Jan. 6 Capitol riot. He also referenced GOA accusations that the U.S. Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) is maintaining an "illegal gun registry" — a reference to a new ATF rule requiring federal firearms licensees to maintain purchase records indefinitely. 

"Gun Owners of America fully agrees with the Weaponization Committee that ‘[d]espite these transactions having no apparent criminal nexus — and, in fact, relate to Americans exercising their Second Amendment rights — FinCEN seems to have adopted a characterization of these Americans as potential threat actors,’" Johnston wrote. 

"This is truly ‘pervasive financial surveillance' of gun ownership and ’raises serious doubts about FinCEN’s respect for fundamental civil liberties,'" he added. 

GOA requested that senators ask Secretary Yellen about these issues and whether the department should be "mass accumulating — or suggesting the mass accumulation of — American citizens' personal firearm transactions."

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The group also requested that senators ask what protections the Treasury has in place "to ensure the privacy of law-abiding Americans who choose to exercise their Second Amendment rights." 

A Treasury Department spokesperson declined to comment.

Fox News' Brooke Singman and Houston Keene contributed to this report.