Republican lawmakers are intensifying their efforts to uncover more information about surveillance of sitting members of Congress conducted under the Biden administration, demanding the release of all prior Justice Department and FBI communications records tied to former special counsel Jack Smith and the bureau’s “Arctic Frost” operation.

Senate Judiciary Committee Chairman Chuck Grassley (R-IA) and Senate Homeland Security investigator Ron Johnson (R-WI) led a letter Friday signed by 16 other GOP colleagues seeking internal records about how FBI agents secretly obtained tolling data from the personal phones of nine Republican lawmakers, including eight senators. The lawmakers are also asking the DOJ to petition the federal judiciary for permission to release records currently shielded by federal grand jury secrecy rules.