If you support Trump, then you are- quite simply- a traitor, and deserve to be dealt with accordingly…

In the days after President Trump fired James B. Comey as F.B.I. director, law enforcement officials became so concerned by the president’s behavior that they began investigating whether he had been working on behalf of Russia against American interests, according to former law enforcement officials and others familiar with the investigation.

The inquiry carried explosive implications. Counterintelligence investigators had to consider whether the president’s own actions constituted a possible threat to national security. Agents also sought to determine whether Mr. Trump was knowingly working for Russia or had unwittingly fallen under Moscow’s influence.

The investigation the F.B.I. opened into Mr. Trump also had a criminal aspect, which has long been publicly known: whether his firing of Mr. Comey constituted obstruction of justice.

Agents and senior F.B.I. officials had grown suspicious of Mr. Trump’s ties to Russia during the 2016 campaign but held off on opening an investigation into him, the people said, in part because they were uncertain how to proceed with an inquiry of such sensitivity and magnitude. But the president’s activities before and after Mr. Comey’s firing in May 2017, particularly two instances in which Mr. Trump tied the Comey dismissal to the Russia investigation, helped prompt the counterintelligence aspect of the inquiry, the people said.

The special counsel, Robert S. Mueller III, took over the inquiry into Mr. Trump when he was appointed, days after F.B.I. officials opened it. That inquiry is part of Mr. Mueller’s broader examination of how Russian operatives interfered in the 2016 election and whether any Trump associates conspired with them. It is unclear whether Mr. Mueller is still pursuing the counterintelligence matter, and some former law enforcement officials outside the investigation have questioned whether agents overstepped in opening it.

Mr. Trump had caught the attention of F.B.I. counterintelligence agents when he called on Russia during a campaign news conference in July 2016 to hack into the emails of his opponent, Hillary Clinton. Mr. Trump had refused to criticize Russia on the campaign trail, praising President Vladimir V. Putin. And investigators had watched with alarm as the Republican Party softened its convention platform on the Ukraine crisis in a way that seemed to benefit Russia.

Other factors fueled the F.B.I.’s concerns, according to the people familiar with the inquiry. Christopher Steele, a former British spy who worked as an F.B.I. informant, had compiled memos in mid-2016 containing unsubstantiated claims that Russian officials tried to obtain influence over Mr. Trump by preparing to blackmail and bribe him.

In the months before the 2016 election, the F.B.I. was also already investigating four of Mr. Trump’s associates over their ties to Russia. The constellation of events disquieted F.B.I. officials who were simultaneously watching as Russia’s campaign unfolded to undermine the presidential election by exploiting existing divisions among Americans.

“In the Russian Federation and in President Putin himself, you have an individual whose aim is to disrupt the Western alliance and whose aim is to make Western democracy more fractious in order to weaken our ability, America’s ability and the West’s ability to spread our democratic ideals,” Lisa Page, a former bureau lawyer, told House investigators in private testimony reviewed by The Times.

“That’s the goal, to make us less of a moral authority to spread democratic values,” she added. Parts of her testimony were first reported by The Epoch Times.

F.B.I. officials viewed their decision to move quickly as validated when a comment the president made to visiting Russian officials in the Oval Office shortly after he fired Mr. Comey was revealed days later.

“I just fired the head of the F.B.I. He was crazy, a real nut job,” Mr. Trump said, according to a document summarizing the meeting. “I faced great pressure because of Russia. That’s taken off.”