If Minnesota officials try to prosecute the federal agents who recently killed two people in Minneapolis, they’ll face steep obstacles from a century-old Supreme Court precedent — one that helped sink a similar case just a few years ago.

Minnesota officials have not explicitly said they will bring criminal charges against ICE and Border Patrol agents responsible for the deaths of Renee Good and Alex Pretti, but Mary Moriarty, the top local prosecutor in Minneapolis, has opened homicide investigations into both shootings. And Minnesota Attorney General Keith Ellison has strongly pushed back on claims that federal agents cannot be prosecuted.

“There is no exemption for federal officers. Nobody gets to commit a crime in Minnesota and be unaccountable for it,” Ellison said on cable news Tuesday night.

But state prosecutors would face significant hurdles.

The 2017 shooting of Bijan Ghaisar by two U.S. Park Police officers in a Northern Virginia neighborhood — and the protracted legal battles that followed — may be the best preview of what Minnesota officials can expect if they pursue criminal charges against federal immigration agents. And the same legal theory that stymied Virginia’s prosecution may also block Minnesota’s.

“It immediately popped into my mind this is potentially going to be a thing that has to happen in state courts,” Fairfax County Commonwealth’s Attorney Steve Descano told POLITICO. “I immediately thought about the Ghaisar case and all of the different standards and all of the procedural hoops people are going to have to go through if they want to bring state charges.”

The FBI investigated the 2017 shooting for two years, but ultimately the Justice Department declined to charge the officers. Following that announcement, Fairfax County prosecutors launched their own criminal investigation but quickly ran into a non-cooperative Justice Department.

Agents who investigated the shooting were not allowed to testify before the Fairfax County grand jury, and the department did not turn over all investigative materials until after the officers had been indicted.

The DOJ said in 2020 that it would not cooperate with Virginia prosecutors because of the possibility that the department would be called to defend the officers in court, according to a letter from then-assistant attorney general for the civil rights division Eric Dreiband.

“It is the longstanding position of the United States that a federal officer may not be prosecuted by a State for actions undertaken in the course of performing the officer’s official duties, when the officer had an objectively reasonable basis to believe that the officer’s actions were necessary to fulfil the officer’s duties,” he added in the letter.