Frey's subpoena requires him to appear in U.S. District Court in Minneapolis on Feb. 3. The Justice Department has not released specific details regarding the focus of the grand jury investigation.

Mayor Frey has publicly criticized the federal government's actions. "We shouldn't have to live in a country where people fear that federal law enforcement will be used to play politics or crack down on local voices," Frey stated, accusing the federal government of weaponizing its power to intimidate local leaders.

The investigation stems from policies enacted during the Trump administration that prioritized stricter immigration enforcement. It is alleged that certain Minnesota officials implemented policies that hindered federal immigration authorities' ability to carry out their duties within the state. These policies reportedly included limitations on information sharing between local law enforcement and federal immigration agencies, as well as restrictions on the ability of local police to detain individuals solely on immigration violations.

Attorney General Ellison's office has not yet released a statement regarding the subpoena. St. Paul Mayor Kaohly Her's office confirmed receipt of the subpoena and stated that they are cooperating with the Justice Department.

NPR has not yet confirmed reports that other state and local leaders have also been issued subpoenas. The Justice Department has declined to comment on the ongoing investigation. The investigation is ongoing, and further developments are expected as the subpoenaed officials comply with the requests for testimony and documents.