A newly released document shows the FBI conducted phone record analysis on eight Republican senators as part of a 2020 election interference investigation led by Special Counsel Jack Smith.

The disclosure came to light Monday when Senator Chuck Grassley released a bombshell document detailing the FBI’s “preliminary toll analysis” conducted in 2023 during President Biden’s term under the “Arctic Frost” probe.

“Based on the evidence to-date, Arctic Frost and related weaponization by federal law enforcement under Biden was arguably worse than Watergate,” the Iowa Republican said in a statement. “If heads don’t roll in this town, nothing changes.”

President Trump responded sharply to the disclosure. “Deranged Jack Smith got caught with his hand in the cookie jar. A real sleazebag!!!” he wrote on Truth Social.

The surveillance targeted eight GOP senators and one House representative. Those monitored included Senators 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 Congressman Mike Kelly of Pennsylvania.

A document dated September 27, 2023, and titled “CAST Assistance” shows the scope of the FBI’s cellular analysis survey team’s activities. The document, which has FBI agent names redacted, shows that investigators conducted “preliminary toll analysis” on phone records associated with the lawmakers.

According to FBI officials, the surveillance allowed Mr. Smith’s team to access phone numbers called by the lawmakers, along with location data showing where calls originated and were received, Fox New reported. The records were obtained in 2023 through subpoenas issued to major telephone providers.

The FBI director, Kash Patel, condemned the surveillance. “We recently uncovered proof that phone records of U.S. lawmakers were seized for political purposes. That abuse of power ends now. Under my leadership, the FBI will deliver truth and accountability, and never again be weaponized against the American people.”

Deputy Director Dan Bongino, who briefed the affected lawmakers on Capitol Hill on Monday, blasted “Arctic Frost.”

“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,” Mr. Bongino told Fox News Digital. “That era is over. Under our leadership, the FBI will never again be used as a political weapon against the American people.”

The Arctic Frost investigation was opened on April 13, 2022, after Mr. Smith was appointed as special counsel in November 2022 to oversee the probe. The investigation focused on alleged attempts to overturn the 2020 presidential election results, with particular attention to the vote certification process.

But a former federal prosecutor, Jeffrey Toobin, provided a different perspective on the surveillance, telling CNN: “It’s not even news. Jack Smith cites these conversations in his report. So this is not like he was trying to keep this a secret. And remember what Smith was investigating. He was investigating Donald Trump’s attempts to overturn the election through the use of fake electors in Congress.”

Mr. Smith’s investigation ultimately led to criminal charges against Mr. Trump in August 2023 in the U.S. District Court for Washington, D.C. However, following Mr. Trump’s victory in the 2024 presidential election, Mr. Smith moved to dismiss the case. Judge Tanya Chutkan granted the dismissal request.

The investigation cost taxpayers more than $50 million before its conclusion.