President Trump has stayed surprisingly quiet as congressional investigators shed new light on the surveillance of people in his orbit, months after making unsupported claims that his predecessor wiretapped Trump Tower.

Obama administration officials attempted to identify Trump's associates in intelligence reports through a process known as "unmasking." Some of the classified information learned through those unmaskings may have found its way into damaging news reports. And FBI agents reportedly surveilled Trump's former campaign manager, Paul Manafort, for weeks at a time in 2016.

"To me, it's notable that Trump hasn't taken these reports to claim any sort of vindication," said Alex Conant, a GOP strategist and former adviser to Sen. Marco Rubio, R-Fla. "Instead, he's staying silent, which hopefully means he's listening to his attorneys' advice and maybe learned lessons from the earlier episodes."

Conant noted Trump may have avoided taking a victory lap after seeing the latest set of developments in the unmasking controversy because the new information is so closely tied to the investigation of his campaign's alleged collusion with Russia.

A probe into how and why Obama administration officials unmasked Trump associates during the campaign and transition has produced early evidence that aides used the procedure with high frequency and may have gathered information about Trump associates' Russian connections through those unmaskings.

Congressional investigators have noticed a potential link between an April story in the Washington Post — in which the identity of a Trump associate was revealed in the context of information that could have been collected through surveillance activities — and an unmasking request made by former national security adviser Susan Rice weeks before the publication of that story, a source familiar with the investigation told the Washington Examiner.

The report described a meeting between Erik Prince, the founder of Blackwater and brother of Education Secretary Betsy DeVos, and an unidentified Russian individual on the island of Seychelles in January. Prince had represented himself during the meeting, which was set up by United Arab Emirates officials, as a conduit for the Trump campaign who was interested in setting up a "back-channel line of communication between Moscow and President-elect Donald Trump," according to the report. Congressional investigators are eyeing a potential connection between the leak of Prince's identity to the media and an unmasking request from Rice that took place in the final days of the Obama administration.

Rice told the House Intelligence Committee earlier this month that she unmasked senior Trump officials in order to understand details of the Trump transition team's contact with UAE officials in January.

Her admission contradicted her earlier claim, in an interview with PBS in March, that she was unaware any Trump officials had ever been unmasked.

"I know nothing about this," she said at the time when asked about the allegation, leveled by House Intelligence Committee Chairman Devin Nunes in March, that the communications of Trump associates may have been swept up in surveillance of foreign targets and their identities subsequently disclosed.

Rice, however, was not the most prevalent unmasking requester in the Obama administration.

Former United Nations Ambassador Samantha Power requested the unmasking of more than 260 Americans during her final year in office, including some requests made in the days just before she left a post that does not typically produce national security justifications for such requests.

Jay Sekulow, one of Trump's personal attorneys, said the "scope and number" of Power's requests concerned him.

"I think the biggest thing is the number of this, it's shocking, it's staggering," Sekulow told the Washington Examiner. "I think what the president was concerned about was a situation where he was surveilled. The media reports at least are indicating, at least, he may well have been."

Beyond the possibility that an unknown number of Trump's associates had their identities exposed in intelligence reports that were then widely circulated throughout the government, Sekulow noted the surveillance of Manafort has raised additional worries.

Investigators reportedly obtained at least two orders to wiretap Manafort both before and after his employment with the Trump campaign through the court authorized by the Foreign Intelligence Surveillance Act.

Manafort has owned a condo in Trump Tower since 2006, and some of the surveillance directed at him during the election could have occurred while he was physically present in that residence. If so, the president could attempt to claim some amount of vindication for his March 4 tweets, in which he claimed he "just found out that Obama had my ‘wires tapped' in Trump Tower" and said the request for such spying was "turned down by [a] court earlier." Critics point out there remains a big factual gap between Trump's tweets and what we currently know.

And experts say the communications collected through the FISA warrant on Manafort would have produced reports from which the names of Americans to whom Manafort spoke — including Trump himself — could be unmasked.

"That type of data would be subject to minimization procedures, and therefore masking of Americans' names would have been done," said Bradley Moss, a national security attorney, referring to procedures implemented to minimize the possibility that Americans' privacy will be infringed by surveillance on foreigners or the targets of criminal investigations.

"The current congressional inquiries into the matter have yet to pinpoint anything specific that was done improperly, although the context of unmasking requests made by Susan Rice and the frequency of requests made by Samantha Power have raised legitimate concerns about ethical abuses that deserve scrutiny," Moss said.

Because senior officials such as Rice and Power had the authority to request unmaskings, however, proving that any of them committed a crime "remains a significant stretch," Moss noted.

"Unless evidence emerges indicating that, for example, Ambassador Power somehow pressured an agency to approve an unmasking request for illegitimate reasons, there simply is not going to be any ‘there' there for a criminal case," he added. "Of course, if Ambassador Power separately disseminated the details of the classified information, including the identity of the unmasked American, to the media, that would be a crime in a separate context."

Trump said on Sept. 14 that the public accounts of Rice's unmaskings are "just the tip of the iceberg" when it comes to her unethical behavior.

So far, however, the embattled president has found little political comfort in the details that have emerged on the surveillance of people in his orbit.

John Feehery, a Republican strategist, argued more evidence could still ultimately surface that would shed light on Trump's claims.

"I think there was a lot of funny business being done to beat Trump," Feehery said. "I don't think we have gotten to the bottom of all of it."