EXCLUSIVE: Former Special Counsel Jack Smith was reportedly tracking the private communications and phone calls of nearly a dozen Republican Senators as part of his investigation into the Jan. 6, 2021, Capitol riots, Fox News Digital has learned.A document, reviewed by Fox News Digital, revealed that Smith and his "Arctic Frost" team investigating Jan. 6 were reportedly tracking the phone calls of GOP Sens. Lindsey Graham of South Carolina, Marsha Blackburn of Tennessee, Ron Johnson of Wisconsin, Josh Hawley of Missouri, Cynthia Lummis of Wyoming, Bill Hagerty of Tennessee, Dan Sullivan of Alaska, Tommy Tuberville of Alabama and GOP Rep. Mike Kelly of Pennsylvania.The document, recently discovered by FBI Director Kash Patel and exclusively obtained by Fox News Digital, is titled "CAST Assistance" and dated Sept. 27, 2023. "CAST" refers to the FBI’s cellular analysis survey team.The document, which has the names of FBI agents involved redacted, marks the case ID as "ARCTIC FROST—Election Law Matters—SENSITIVE INVESTIGATIVE MATTER—CAST."FLASHBACK: ANTI-TRUMP FBI AGENT RESPONSIBLE FOR OPENING JACK SMITH ELECTOR CASE AGAINST PRESIDENT: WHISTLEBLOWERThe document states the names of the lawmakers and that an FBI special agent on Smith’s team "conducted preliminary toll analysis" on the toll records associated with the lawmakers. An FBI official told Fox News Digital that Smith and his team tracking the senators were able to see which phone numbers they called, the location the phone call originated and the location where it was received.A source said the calls were likely in reference to the vote to certify the 2020 election. An official said the records were collected in 2023 by Smith and his team after subpoenaing major telephone providers. "Arctic Frost" was opened inside the bureau April 13, 2022. Smith was appointed as special counsel to take over the probe in November 2022. Fox News Digital has learned that FBI Deputy Director Dan Bongino is briefing those lawmakers on the discovery of Smith’s surveillance Monday afternoon on Capitol Hill.A source said Bongino and FBI Director Patel felt it was important to brief the senators "as soon as possible" after the discovery of the record."It is a disgrace that I have to stand on Capitol Hill and reveal this — that the FBI was once weaponized to track the private communications of U.S. lawmakers for political purposes," Bongino told Fox News Digital. "That era is over."Bongino added: "Under our leadership, the FBI will never again be used as a political weapon against the American people."FBI officials told Fox News Digital that the newly discovered records were pursuant to an oversight request by Sen. Chuck Grassley, R-Iowa.Patel and Bongino personally directed additional review of the "Arctic Frost" case after Grassley’s request.An FBI official told Fox News Digital that "Arctic Frost" is a "prohibited case," and that the review required FBI officials to go "above and beyond in order to deliver on this promise of transparency." The discovery is part of a broader ongoing review, Fox News Digital has learned.CLICK HERE TO GET THE FOX NEWS APP"The American people deserve the truth, and under my leadership, they will have it," Patel told Fox News Digital. "We promised accountability for those who weaponized law enforcement, and we will deliver it."Patel added: "Under our watch, the FBI will never again be turned against the American people."Smith, after months of investigating, charged President Donald Trump in the U.S. District Court for Washington, D.C., in his 2020 election case, but after Trump was elected president, Smith sought to dismiss the case. Judge Tanya Chutkan granted that request. Smith's case cost taxpayers more than $50 million.