The special counsel Robert Mueller is preparing to move forward without an interview with President Donald Trump in his obstruction-of-justice case, according to NBC News.

Trump was leaning toward granting Mueller an interview but is said to have decided against it following the FBI's raids of his personal lawyer's hotel room and office this week.

Experts say that even without an interview with Trump — who's at the center of the obstruction case — Mueller most likely has enough evidence to present his findings to Congress.

The special counsel Robert Mueller's team is moving forward on the assumption that it will not secure an interview with President Donald Trump, NBC News reported Thursday.

Trump's lawyers and Mueller's team had for months been negotiating the terms of an interview between the two sides.

On Monday, NBC News reported, Trump's lawyers were in the final stages of determining the scope, timing, and length of an interview and were poised to bring attorneys onto the team to prepare Trump for the impending sit-down. But those talks fell through when it surfaced that the FBI that morning raided the hotel room and office of Michael Cohen, Trump's personal lawyer.

The raid apparently enraged Trump, who believes it crossed the "red line" he said investigators would breach if they looked into his or his family's finances.

Earlier this month, The Washington Post reported that Mueller's team was putting together a report about Trump's conduct in office and possible obstruction of justice.

Mueller is tasked with investigating Russia's interference in the 2016 US election, and a significant thread in the inquiry is whether the president sought to obstruct justice when he fired James Comey as FBI director last year.

Comey had publicly confirmed the existence of the Russia investigation months before his firing, and he was in charge of overseeing it at the time of his dismissal.

Since then, news reports and a string of public statements from Trump have raised questions about the circumstances surrounding Comey's firing and whether Trump had the right to fire the FBI director if his intent were to hamper a criminal investigation involving him and his associates.

In addition to Comey's firing, Mueller was also looking into Trump's role in crafting a misleading statement his eldest son, Donald Trump Jr., released in response to reports that he met with two Russian lobbyists in June 2016, and into Trump's efforts to pressure Attorney General Jeff Sessions to reverse his recusal from the Russia investigation.

And in a new development, NBC News reported that Mueller was investigating whether Trump's former lawyer floated pardons to critical witnesses in the investigation.

According to the report, Mueller has collected evidence on all those threads in the obstruction inquiry.

Mueller's team was aiming to finalize the report on its findings as early as May or as late as July. But if the special counsel has decided to proceed without an interview, the timeline may shorten.

The outlet described two sources familiar with the investigation as expecting "a flurry of activity" out of Mueller's office in the next six weeks.

Alex Whiting, a former federal prosecutor who is now a professor at Harvard Law School, said the NBC News report wasn't surprising.

"I am sure that Mueller's team has enough evidence to draw conclusions on the obstruction prong without an interview with Trump," Whiting said. "An interview of the potential target of the investigation is always helpful, but most criminal investigations conclude without such an interview, because targets assert their Fifth Amendment privilege not to testify."

Subpoenaing Trump is a 'strategic choice' that Mueller most likely won't pursue

U.S. President-elect Donald Trump speaks with his son Donald Trump Jr. during a news conference in the lobby of Trump Tower in Manhattan, New York City, U.S., January 11, 2017. REUTERS/Lucas Jackson

Mueller has the option of subpoenaing Trump for an interview, but legal experts unequivocally said that would lead to a prolonged battle in court.

NBC News reported that if Trump were to decline a voluntary sit-down with the special counsel, his lawyers would argue that because a sitting president cannot be indicted, he also cannot be subpoenaed.

Whiting said that whether Mueller subpoenas Trump to testify before a grand jury was "really a strategic choice."

"He will have to decide whether it is worth the time to litigate the matter," he said. "Even if they prevailed on the subpoena, Trump himself could always assert his Fifth Amendment privilege, though it would be politically costly to do so."

For that reason, Mueller is likely to move ahead with putting together his report without an interview.

News that Mueller is preparing a report about those circumstances lays out some important clues about the direction of the investigation.

It could indicate one of three things, according to Jeffrey Cramer, a former federal prosecutor who spent 12 years at the Department of Justice:

The president did nothing wrong and will not be charged. Mueller found some indication of criminal activity but might not have enough evidence to indict Trump. Mueller does have enough evidence to indict Trump but may decide he does not have the authority to charge the president based on Department of Justice precedent.

Legal experts say that because of existing Justice Department policy, it is unlikely Mueller will indict Trump if he has found evidence of wrongdoing.

They added that the decision about how to proceed once Mueller issues his report would fall to Congress, which is authorized to impeach the president — and where such a document could prove most consequential.

Mueller's office has so far charged 19 people, including 13 Russian nationals. The indictments — as well as the charges against Paul Manafort, the former Trump campaign chairman — draw a stark and detailed picture of the allegations of criminal conduct.

"Similar to the Manafort and Russian indictments, I expect any report [about Trump] to lay out in painstaking detail the facts they uncovered," Cramer said.

Mueller is mandated to provide reports of his findings to Rod Rosenstein, the deputy attorney general who appointed him as the special counsel in May. But whether those findings are released to the public is Rosenstein's decision.

Whiting said he found it "striking" that "Mueller seems to be preparing the report with an expectation that it will eventually become public."

He added: "Once the investigation is completed, I think it will be very difficult to keep Mueller's conclusions secret."