The investigation will look into whether Minnesota officials blocked federal immigration agents from carrying out their duties.

Minnesota Governor Tim Walz, Attorney General Keith Ellison and Minneapolis Mayor Jacob Frey are among a group of state officials who say they are under investigation by the US Department of Justice (DOJ), a week after they sued the federal government over its controversial immigration raids.

The DOJ probe will review whether Minnesota state officials conspired to obstruct justice by preventing federal immigration officers from carrying out their duties, US broadcaster CBS News reported late on Tuesday.

The investigation is the latest twist in an escalating showdown between Minnesota officials and the administration of President Donald Trump over immigration raids in the state, including the operation where an Immigration and Customs Enforcement (ICE) agent shot dead Renee Good, a mother of three and a US citizen.

Governor Walz confirmed the DOJ investigation in a statement on Tuesday, describing the move as “political theatre”.

“This Justice Department investigation, sparked by calls for accountability in the face of violence, chaos and the killing of Renee Good, does not seek justice. It is a partisan distraction,” he said.

In a post on X, Attorney General Ellison said the Justice Department had subpoenaed his office for “records and documents related to my office’s work with respect to federal immigration enforcement, not for me personally”.

Ellison called the move “highly irregular”, given the timing of the order so soon after the state filed a January 12 lawsuit against the Department of Homeland Security, which oversees ICE and Customs and Border Protection (CBP).

“Trump’s DOJ is more focused on investigating my office than the killing of Renee Good,” Ellison wrote on X.

“I will not be intimidated, and I will not stop working to protect Minnesotans from this campaign of revenge,” he said.

In a statement announcing the federal lawsuit last week, Ellison’s office said the ICE raids were “dangerous, illegal, and unconstitutional stops and arrests, all under the guise of lawful immigration enforcement”.

Minneapolis Mayor Frey described the DOJ investigation as an attempt to intimidate state officials.

Frey’s office earlier released a copy of the Justice Department subpoena, which calls for “any records tending to show a refusal to come to the aid of immigration officials”, according to The Associated Press news agency.

The documents will be reviewed by a grand jury on February 3, which will assess whether there is probable cause to proceed with the lawsuit.

The Department of Homeland Security launched an enormous immigration operation to deploy thousands of ICE and CBP officers to the Minnesota cities of Minneapolis and St Paul – known as the “Twin Cities” – in December, as part of Trump’s crackdown on undocumented immigrants in Democrat-led cities.

The Minnesota crackdown became global news in early January when an ICE officer shot and killed Good, 37, who was monitoring an immigration raid as a citizen observer. The DOJ has since declined to investigate the shooting despite widespread public outrage across the country.

Trump has threatened to use the Insurrection Act against the state and has readied 1,500 active-duty soldiers in Alaska to prepare to deploy to Minnesota to quell potential protest violence, according to a Reuters report, citing unnamed US officials.