WASHINGTON — Federal prosecutors' decision to end an investigation into hush money payments to women claiming affairs with Donald Trump relied at least in part on long-standing Justice Department policy that a sitting president cannot be charged with a crime, a person familiar with the matter said Thursday.

The Justice Department told a federal judge on Monday that it had "effectively concluded" its investigation into efforts to silence the women in the final months of the 2016 campaign, but did not explain why it had done so. Prosecutors have said the payoffs violated a federal law that restricts campaign donations.

A person familiar with the case, who was not authorized to discuss it publicly, said it was unclear whether prosecutors made a determination that they had sufficient evidence to bring a case against Trump or anyone other than his former personal lawyer, Michael Cohen, who pleaded guilty last year. But the Justice Department's opinion that a president cannot be indicted factored into the decision to end the probe, the person said.

Federal prosecutors had repeatedly placed Trump at the center of the effort to silence pornographic actress Stormy Daniels and former Playboy model Karen McDougal during the chaotic run-up to the 2016 election. Last year, they alleged in a court filing that Cohen had orchestrated illegal hush-money payments "in coordination with and at the direction of" Trump. And it revealed in unsealed court records on Friday that Trump participated in phone calls about the payments to Daniels.

The judgment by federal prosecutors in New York to take no further action in the wide-ranging inquiry tracks a decision earlier this year by former special counsel Robert Mueller, who cited the same Justice Department policy when he declined to make a determination about whether Trump's efforts to derail that investigation amounted to a crime.

The Justice Department's Office of Legal Counsel concluded in 2000 that "a sitting President is constitutionally immune from indictment and criminal prosecution." That view has never been tested in court but is binding on federal prosecutors.

As in the Mueller inquiry, which outlined 10 instances in which Trump sought to thwart the special counsel's inquiry, documents revealed Thursday put then-candidate Trump in middle of a frantic effort to fend off damaging disclosures about his personal conduct just a month before the 2016 election.

In the documents, the FBI described a series of conversations in the days after a leaked Access Hollywood outtake showed Trump boasting about grabbing women by the genitals about preventing Daniels from airing her own claims of having had an affair with Trump years earlier.

Authorities laid out a timeline of emails, text messages and phone calls – some involving Trump himself – that "concerned the need to prevent" Daniels from going public with her story.

Trump denied knowledge of the payments after they became public. But the FBI told a judge it had obtained telephone records showing he participated in some of the first conversations about the scheme, which prosecutors have said violated federal campaign finance laws.

Federal prosecutors said in court filings last year that Cohen orchestrated payments to Daniels and McDougal, "in coordination with and at the direction of" Trump. The documents unsealed Thursday offer the first clear account of the extent of Trump's involvement in that effort, as the Republican nominee's campaign floundered just weeks before the election.

Ultimately, it was Cohen – not Trump – who was charged and convicted for the scheme. He is serving a three-year sentence in federal prison related to tax evasion and the hush-money scheme that amounted to illegal campaign finance violations. He also pleaded guilty to Congress about efforts to build a Trump Tower in Moscow during the 2016 campaign.

"Cohen's commission of two campaign finance crimes on the eve of the 2016 election for president of the United States struck a blow to one of the core goals of the federal campaign finance laws: transparency," prosecutors asserted prior to Cohen's sentencing.

In the same document, however, prosecutors indicated that Cohen was acting on behalf of Trump who they then-described in gauzy law enforcement vernacular as "Individual 1."

"The investigation is over," Trump attorney Jay Sekulow said Thursday. He declined to address whether the current Justice Department policy against prosecuting a sitting president blocked any further action contemplated by New York prosecutors.

The Justice Department did not respond to a request for comment.

But from a federal prison in upstate New York, Cohen continued to claim that his conviction should not mark the end of an investigation that has long shadowed the White House.

"I and members of The Trump Organization were directed by Mr. Trump to handle the Stormy Daniels matter; including making the hush money payment,” Cohen said in a statement Thursday. “The conclusion of the investigation exonerating The Trump Organization's role should be of great concern to the American people and investigated by Congress and the Department of Justice.”

House Intelligence Committee Chairman Adam Schiff, D-Calif., said the unsealed documents bolstered Cohen's assertions.

"The inescapable conclusion from all of the public materials available now is that there was ample evidence to charge Donald Trump with the same criminal election law violations for which Michael Cohen pled guilty," Schiff said.

Contributing: Nicholas Wu

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