The US justice department is investigating Minnesota’s political leaders for allegedly conspiring to obstruct the Trump administration’s controversial immigration crackdown there, according to multiple reports.

The investigation, which CBS News first reported, marks an extraordinary use of federal power to challenge two of the crackdown’s most vocal Democratic critics, including the state’s governor, Tim Walz, and the mayor of Minneapolis, Jacob Frey.

Walz, who was also the Democratic nominee for vice-president in 2024, responded to news of the investigations in a post on social media.

“Two days ago it was Elissa Slotkin. Last week it was Jerome Powell. Before that, Mark Kelly. Weaponizing the justice system against your opponents is an authoritarian tactic,” Walz wrote. “The only person not being investigated for the shooting of Renee Good is the federal agent who shot her.”

In a statement to the Minnesota Star Tribune, Frey said: “I will not be intimidated.”

This is an obvious attempt to intimidate me for standing up for Minneapolis, our local law enforcement and our residents against the chaos and danger this administration has brought to our streets,” the mayor added.

“My focus will remain where it’s always been: keeping our city safe. America depends on leaders that use integrity and the rule of law as the guideposts for governance. Neither our city nor our country will succumb to this fear. We stand rock solid.”

The Washington Post reports that the justice department has already issued subpoenas for both men, and intends to serve them within hours.

The shooting of Rene Good by ICE officer Jonathan Ross last week set off nationwide protests and turned Minneapolis into a flashpoint of resistance to the Trump administration’s increasingly draconian immigration crackdown. Homeland security has deployed about 3,000 immigration enforcement officers to Minnesota, which is five times the size of the Minneapolis police force.

Local and federal officials have also clashed over the investigation into Ross’s shooting. A New York Times analysis of witness videos appeared to show that Ross had sidestepped the car Good was driving and she did not present a threat to him as he drew his service pistol and fired on her three times at close range.

But federal authorities, including Donald Trump and his vice-president, JD Vance, have repeatedly defended Ross’s actions and the FBI took the unusual step of refusing to cooperate with state investigators, who have the power to bring criminal charges against Ross if warranted, but need access to evidence to do so.

The deputy attorney general, Todd Blanche, appeared to allude to the coming investigation in a statement on X earlier this week.

“Minnesota insurrection is a direct result of a FAILED governor and a TERRIBLE mayor encouraging violence against law enforcement,” Blanche tweeted. “It’s disgusting. Walz and Frey – I’m focused on stopping YOU from your terrorism by whatever means necessary. This is not a threat. It’s a promise.”

Trump has repeatedly directed the justice department to pursue criminal investigations and prosecutions against his political opponents since retaking office last year.