Herman Ouseley has called for the Football Association to provide more clarity about an independent investigation into claims the England manager, Mark Sampson, and his staff were abusive towards Eni Aluko.

Lord Ouseley, the chairman of the anti-discrimination organisation Kick It Out, said he found it contradictory the FA had paid Aluko upwards of £40,000 despite the investigation and a separate internal review apparently finding there was no case to answer.

Aluko has not played for England since April last year, despite being the top scorer in the women’s Super League last season. In an eight-page complaint, seen by the Daily Mail, Aluko details what she claimed was two years of “bullying and harassment” within the national squad.

On one occasion she claimed that in video analysis from a match, a coach on the touchline says: “Her [Aluko’s] fitness results are good,” to which another one replies: “Yeah, but she is lazy as fuck.”

The investigation, conducted by the barrister Katharine Newton, from Old Square Chambers, concluded in March this year and found no wrongdoing on the part of Sampson and his staff. The FA renewed Aluko’s £20,000 contract even though the 30-year-old stated she would not be able to play “under his [Sampson’s] management”.

In addition she was paid an extra £40,000 and asked to sign a confidentiality agreement. The FA denies this was a gagging order and claims instead it was to “avoid disruption” to the England squad who reached the Euro 2017 semi-finals in the Netherlands this month.

But, with the tournament over, Ouseley urged the FA or Aluko to provide more clarity about the facts of the case and how the ruling was reached. “Our concern is to get clarity,” he said. “We need to know the FA has processed this case correctly.

“As an organisation we are very much on top of what happens on the pitch and with fans but, with regard to the FA’s own employees, we need to know they are not just buying people off and taking no remedial action.

“The FA says it was a thorough investigation but we need to understand why they would pay someone such a large amount after two investigations found there was no case to answer.

“I understand why they wouldn’t want it to be public and distract from Euro 2017 but now is the time for Eni herself or the FA to speak. It needs someone to come clean on this.”

England won all their group games in the Netherlands and eliminated France in the quarter-finals before losing 3-0 to the hosts. Holland went on to win the tournament after beating Denmark 4-2 in Sunday’s final.