Former President Donald Trump said he has been notified that he is a target in the Justice Department’s investigation into efforts to overturn the 2020 election results, signaling that he is likely to be charged with federal crimes.

In a post on his Truth Social account Tuesday, Trump said he received the notice Sunday night from Special Counsel Jack Smith, who is investigating Trump’s actions in the aftermath of the presidential election, including the insurrection at the US Capitol on Jan. 6, 2021.

The letter stated that he is a target of the grand jury investigating efforts to overturn the election result and the Jan. 6 attack, indicating that prosecutors have specifically zeroed in on his actions and have substantial evidence that he committed crimes.

Trump said he was given four days to testify before the grand jury. He said he expects to be charged because such a move “almost always means an arrest and indictment.”

A spokesman for Smith and the Justice Department declined to comment.

If the Justice Department brings charges against Trump in the Jan. 6 investigation, it will mark an aggressive, unprecedented and monumental development. Trump is already under federal indictment for allegedly mishandling classified materials and he faces an indictment in state court in Manhattan over payments to a porn star. He is currently the frontrunner to be the Republican candidate for president in next year’s election.

The Justice Department’s decision to charge Trump under President Joe Biden — his Democratic rival in the last presidential race and expected opponent if Trump is the 2024 Republican nominee — is also expected to send shock waves through the two-party US political system and sets in motion what is likely to be a ferocious legal battle that could make its way to the US Supreme Court.

It isn’t clear what specific charges might be brought against Trump, but the Justice Department has successfully prosecuted individuals for their actions related to the Jan. 6 attack with crimes ranging from interference in an official government proceeding to seditious conspiracy.

Trump has a track record of previewing legal developments against him and using his public platforms to try to control the narratives surrounding them. For example, Trump announced he had been indicted in the classified documents probe before the charges were announced.

Special Counsel Smith has been leading the sprawling investigation into actions taken by Trump, his allies and his lawyers in the weeks and days leading up to the Jan. 6 attack. Avenues that have been explored by prosecutors include efforts to organize slates of false electors in battleground states that Trump lost and to pressure former Vice President Mike Pence to interfere with the certification of the results by Congress.

In the Mar-a-Lago classified documents case, Trump was notified he was a target on May 19. His lawyers met with Justice Department officials on June 5 after requesting a sitdown; he was indicted three days later.

The judge overseeing Trump’s criminal case in Florida over his handling of classified documents is scheduled to hold a pretrial hearing Tuesday at 2 p.m. in Fort Pierce, Florida, to hear arguments from prosecutors and the former president’s lawyers regarding the handling of classified evidence in the case and timing of a trial.

--With assistance from Zoe Tillman and David Voreacos.

(Updates with more context starting in the fourth paragraph.)