But the case was dismissed by a Serie A sports judge on Tuesday because of a lack of evidence.

As a result, Napoli said they will not take part in anti-racism initiatives.

"We find it astonishing," said the Italian club in a statement.

"The principle of the greatest likelihood of an event, which exists in sports justice and which appears clear from the dynamics of the incident and the apology offered on the pitch, simply vanishes in this judgement.

"Napoli will no longer take part in anti-racism and anti-discrimination initiatives run by football institutions that are merely symbolic, but we will continue to organise them ourselves, as we have always done, with renewed conviction and determination."

Acerbi withdrew from the Italy squad for friendlies against against Venezuela and Ecuador last week following the allegations.

A statement from the Italian federation said Acerbi had said there was "no defamatory, denigrating or racist intent" to his comments.

Judge Gerardo Mastrandrea suggested Acerbi's comments to Brazilian defender Jesus may have been offensive but could not say whether they were of a racist nature because of a lack of evidence.

"Without calling into question the good faith of the Napoli player, it appears to have been perceived only by 'offended' footballer without the support of any external evidence, be it audio, video or even testimonial," the ruling said.

But Napoli responded: "If what happened on the pitch 'is certainly compatible with the expression of offensive comments by the Inter player, who does not deny that they were offensive and threatening', then why was Acerbi not sanctioned in any way?

"If, as the judgement itself reads, 'there was certainly proof of an insult', why did the sports judge decide to take no action to punish the responsible party?

"We find that even more astonishing."

Acerbi is free to play in Inter's first game after the international break on Monday against Empoli.