The FBI's scrutiny of Donald Trump's wider presidential campaign team over fears of collusion with Kremlin election-meddling began as far back as the summer of 2016, according to the former FBI Director James Comey.

Comey revealed in testimony to congressional investigators that four Americans somehow connected to the campaign, but not Trump himself, had come into the FBI's sights in late July, well before polling day.

The details were made public for the first time on Saturday when the House Judiciary and Oversight and Government Reform committees released the transcript of Friday's seven-hour, closed-door interview with Comey.

Comey’s statements provide new information about the timing of the federal government’s probe into the 2016 presidential battle between Trump and Democrat Party nominee Hillary Clinton, and could offer new clues about what’s coming down the pipeline from the Department of Justice.

Comey’s revelation comes as the investigation led by Special Counsel Robert Mueller picks up speed in its issuing of sentencing and cooperation memos for several former Trump associates. In the past two weeks Mueller’s team has provided the public with vast new details about the lies of former campaign chairman Paul Manafort, the cooperation of former National Security Advisor Michael Flynn and the nefarious business dealings of Michael Cohen.

Comey divulged the details of the four Americans connected to Trump in an exchange with Republican Rep. Trey Gowdy.

“Late July of 2016, the FBI did, in fact, open a counterintelligence investigation into, is it fair to say the Trump campaign or Donald Trump himself?” Gowdy asked.

“It's not fair to say either of those things, in my recollection,” Comey replied. “We opened investigations on four Americans to see if there was any connection between those four Americans and the Russian interference effort. And those four Americans did not include the candidate.”

Comey did not name the four Americans. But he mentioned them again later in the interview when Rep. Sheila Jackson Lee, a Democrat, pressed him further.

“Those individuals were affiliated with the campaign?” she said. “I believe they were in some form.”

“At least some of them were,” he replied. “The FBI and the Department of Justice have not confirmed the names of those folks publicly, which is why I'm not going into the specifics.”

Comey also came to the defense of Peter Strzok, a former FBI agent who headed the counterintelligence operation into Hillary Clinton’s use of her personal email server. Strzok also worked on Mueller’s investigation but was fired in summer of 2017 when text messages were released that showed he had spoken unfavorably about Trump.

After questioning about the former agent from Democratic Rep. Steven Cohen, Comey said he never saw any bias from Strzok.

“It's hard for me to see how he was on Team Clinton secretly at that point in time,” Comey said. “He also was one of the handful of people in the entire world who knew we were investigating four Americans who had some connection to Mr. Trump during the summer of 2016, and he didn't tell a soul.”

Later in the interview, Comey said the FBI suspected those four Americans may have helped the Russians meddle in the election. The revelation came when Rep. John Ratcliffe, a Texas Republican, asked him if the FBI suspected any Americans of colluding with Russians when it briefed the Trump campaign on potential intelligence threats.

“[A]t the time a defensive briefing was done for candidate Trump, do you know if the FBI had any evidence that anyone associated with the Trump campaign had colluded or conspired or coordinated with Russia in any way?” Ratcliffe asked.

“I don't know the dates... I don't know whether it was before late July when we opened the four counterintelligence files, or not,” Comey replied. “And so, if it was after July 29th, then the answer would be, yes, we had some reason to suspect that there were Americans who might have assisted the Russians.”

It has been widely reported that Mueller is probing various members of the Trump team and those who either worked or associated themselves with the campaign. He’s indicted several of those individuals over the past year, including George Papadopoulos, a former member of Trump’s foreign policy advisory panel, Rick Gates, a former campaign aide, Manafort, Cohen and Flynn. Mueller has also reportedly questioned Jared Kushner and solicited written responses from President Trump.

Representatives in the closed-door interview posed several questions to Comey about the special counsel’s investigation into obstruction. At one point Gowdy asked Comey about his termination from the FBI.

“He is entitled to his opinion, but to the extent—because he also stated that he is also a witness in the investigation,” said Cecilia Bessee, a lawyer for the FBI present at the interview.

“Which investigation is he a witness in?” Gowdy asked.

“To the special counsel,” Bessee said, switching her phrasing on Comey’s witness status. “He said he is a potential witness.”

“Well, you just said witness,” Gowdy said. “Is there an obstruction of justice investigation?”

“I believe there is an investigation that the special counsel is looking into,” Bessee said.

It’s unclear if Comey has been questioned by the special counsel’s office or what information Mueller would seek from the former FBI director.

Comey refrained from answering questions about the memo Deputy Attorney General Rod Rosenstein wrote appointing Mueller as special counsel. However, he told lawmakers his views on the conception of the overarching probe and the hot button term “collusion.”

“The term ‘Russia investigation’ often refers to two different things: first, the investigation to understand what are the Russians doing to interfere in our election during the 2015-16 period; and then, second, it's often used to refer to the counterintelligence investigations that the FBI opened in late July,” Comey said, adding that he did not understand what the word “collusion” meant.

“I've never heard the term ‘collusion’ used in the way it's been used in our world over the last couple years before that,” Comey said.  “I don't know of a crime that involves collusion.”