Paranoia has spread through the halls of the White House as the Federal Bureau of Investigation closes in on the Trump administration.
Robert Mueller's probe into whether the Trump campaign helped the Russians to meddle in last year's presidential election claimed its biggest scalp on Friday when former senior staffer Michael Flynn admitted to lying to the FBI about his contacts with the Kremlin.
But buried in Flynn's 10-page plea agreement is a line that has White House staffers watching their backs and choosing their words carefully: "Your client's co-operation may include … participating in covert law enforcement activities."
The military veteran is the second Trump insider to flip and agree to co-operate with the Russia probe.
Campaign staffer George Papadopoulos was hit with similar charges in October when it was revealed he had also lied to the FBI about his contacts with Russian government operatives.
The big worry for Trump aides is that there were three months between his arrest and the announcement of his plea deal, which led Washington watchers to speculate that he may have used the time in between to gather evidence against the campaign.
The fear enveloping the White House is that both men may have worn wires to secretly tape conversations before their charges were revealed.
"Everyone is paranoid," a Trump White House insider told Politico. "Everyone thinks they're being recorded."
A lawyer representing a senior Trump staffer added to Politico: "They're probably s***ting bricks. How can you not?"
The one protection that White House staffers have is that it is illegal to secretly record anyone who already has legal representation in regards to the Russia investigation.
White House lawyer Ty Cobb dismissed the idea that these worries are consuming the White House.
"I don't know anyone who feels that paranoia," Cobb told Politico. "To the uninformed and inexperienced this may be enjoyable. But in reality, it is unhinged speculation with no foundation."
What was notable about Friday's developments is that Flynn will only face one charge of lying to the FBI. That indicates he may have negotiated a lesser charge in exchange for giving up dirt on the Trump team.
Despite all the smoke, the Mueller investigation is yet to present evidence that the Trump campaign had any illegal interactions with the Russian government.
TRUMP KNEW FLYNN LIED TO FBI: REPORT
In a significant development overnight, CNN reported that Trump knew that Flynn lied to the FBI before he allegedly asked FBI director James Comey to "let go" the investigation into his former national security adviser.
The White House's chief lawyer informed Trump in January that he believed Flynn had misled the FBI and Vice-President Mike Pence over his dealings with the Russian ambassador to the US, according to CNN.
Comey said that, in a private meeting on February 14, Trump said: "I hope you can see your way clear to letting this go, to letting Flynn go."
The timeline is significant because it gives credence to the Democrats' allegation that Trump obstructed justice in the Russia investigation, which is a federal crime.
The President has denied asking Comey to drop the Flynn investigation.
Meanwhile, Trump's lawyer has advanced a controversial defence against claims of obstruction of justice.
"The President cannot obstruct justice because he is the chief law enforcement officer under [the Constitution's Article II] and has every right to express his view of any case," John Dowd told Axios.
TRUMP SAYS FBI'S REPUTATION IN 'TATTERS'
Meanwhile, the President has launched an extraordinary attack on the US's top law enforcement agency, the FBI.
Trump had a ferocious weekend on Twitter, blasting Hillary Clinton, the Justice Department and the "fake news" media, but his most extraordinary criticism was levelled at the bureau. He placed much of the blame at the feet of former director James Comey, who he fired in May.
"After years of Comey, with the phony and dishonest Clinton investigation (and more), running the FBI, its reputation is in Tatters — worst in History! But fear not, we will bring it back to greatness," Trump tweeted on Sunday.
Barack Obama's Attorney-General Eric Holder took exception to the spray and stepped in to defend the bureau's 35,000-strong workforce.
"Nope. Not letting this go. The FBI's reputation is not in 'tatters'. It's composed of the same dedicated men and women who have always worked there and who do a great, apolitical job," he tweeted.
"You'll find integrity and honesty at FBI headquarters and not at 1600 Penn Ave right now."
Comey also tweeted in defence of the bureau.
Trump pointed to the suspension of Peter Strzok as evidence of political bias within the organisation.
Strzok, a veteran counterintelligence agent, was benched from his role as a special prosecutor in the Russia probe after it came to light he had exchanged anti-Trump text messages with a colleague. The agent had also played a leading role in the investigation into Clinton's questionable use of her private email server for official business when she was the secretary of state.
When asked about Flynn on the South Lawn of the White House on Monday morning, Trump said he felt "very badly" for his former national security adviser.
"I will say this: Hillary Clinton lied many times to the FBI and nothing happened to her. Flynn lied and they destroyed his life. I think it's a shame," the President told reporters.
"Hillary Clinton, on the Fourth of July weekend, went to the FBI, not under oath — it was the most incredible thing anyone has ever seen. She lied many times. Nothing happened to her. Flynn lied, and it's like they ruined his life. It's very unfair."
However, the FBI has concluded that Clinton was telling the truth when she was interviewed.
"We have no basis to conclude she lied to the FBI," Comey told a congressional committee last year while under oath.