Katharine Newton, the barrister in charge of the controversial inquiry into Mark Sampson’s conduct as England Women’s manager, has changed her position behind the scenes and intends to interview the three players who have been identified as key witnesses but were overlooked for her initial investigation.

Newton has already spoken to Drew Spence as part of the reopened inquiry and the Guardian has learned the barrister, heavily criticised for her initial three‑month investigation, will now meet two Manchester City players, Jill Scott and Izzy Christiansen, and Reading’s Jo Potter, to establish what Sampson allegedly said in a meeting during the China Cup in October 2015.

At least two of those players are understood to have key information but were never consulted when Newton’s initial findings ruled there had been no wrongdoing, clearing Sampson of the allegation that he had asked Spence, a mixed-race player on her first England camp, how many times she had been arrested.

Sampson was also cleared by an internal review but lost his job last week after the FA’s highest-ranking officials admitted they were unaware of his safeguarding history, an admission that has left the chief executive, Martin Glenn, and the chairman, Greg Clarke, facing considerable scrutiny over their own positions.

The crisis was discussed at length at an FA board meeting on Monday and an investigation has been launched into how the full report into Sampson, containing details of “inappropriate and unacceptable behaviour” from his previous coaching role at Bristol Academy, went two and a half years without being seen by the people at the top of the organisation.

The FA’s safeguarding officers concluded their report in March 2015 and that has left the governing body facing difficult questions about how it went so long without knowing the details of an investigation that led to Sampson being sent on an educational course.

However, the statement released by the FA made it clear that Glenn and Clarke still had the board’s support. “The board is confident that, consistent with the substantial positive change under the leadership of Greg Clarke and Martin Glenn, the right procedures are in place to prevent a similar issue arising now or in the future,” it read.

With Newton now on her second investigation, on top of the FA’s internal review, the inquiry into the events that eventually cost Sampson his job, as well as the safeguarding one, means the governing body is now on its fifth process of this nature about a man who has been accused of having inappropriate relationships with players at Bristol and asking an England international, Eni Aluko, to make sure her Nigerian relatives did not bring the Ebola virus to Wembley.

Sampson has always denied making racial comments to Spence and Aluko but the Professional Footballers’ Association has accused the FA’s technical director, Dan Ashworth, and the human resources director, Rachel Brace, of not conducting “a genuine search for the truth” and overseeing a “sham” that was “designed to close down the complaint and absolve Mark Sampson”.

Ashworth was not mentioned in the FA’s statement but also appears to have the backing of his colleagues after being handed the role of finding Sampson’s successor. Ashworth has refused to discuss his involvement in the story but could conceivably be one of the officials who has to face the digital, culture, media and sport select committee on 18 October. Aluko and a second former England player, Lianne Sanderson, have been invited to give evidence after what the sports minister, Tracey Crouch, has described as a “mess”.

“The Football Association must explain why it took so long to look into issues raised about the coach’s past,” Damian Collins, the committee chairman, said in a statement. “Why was he appointed in the first place? Why didn’t senior officials refer back to this information when a player stepped forward with serious allegations?

“Players have a reasonable right to expect their concerns will be taken seriously. The committee will ask why senior leadership at the FA failed to act without prompting from external organisations. This raises serious questions about their capacity to run internal investigations.”