The president of FC Barcelona, Joan Laporta, said on Monday that all payments made by the soccer club to a company owned by a senior refereeing official were for advisory matters and not to gain any illegal sporting advantage.
Laporta said an internal investigation conducted by the club did not show any wrongdoing and he said the case was an orchestrated campaign to discredit Barcelona.
He accused the president of LaLiga, Javier Tebas, of "trying to damage Barcelona's reputation".
He also attacked their rivals Real Madrid, who have joined the prosecutor's case against Barcelona, saying Real had always been historically favoured by refereeing.
Spanish prosecutors last month filed a complaint against Barcelona over payments of 7.3 million euros ($7.95 million) from 2001 to 2018 to firms owned by Jose Maria Enriquez Negreira.
Negreira was vice-president of the refereeing committee of the Spanish Football Association from 1993 to 2018.
A Barcelona court has agreed to take the case. UEFA has also opened a formal investigation for a potential violation of the European soccer governing body's legal framework over the Negreira case.
Laporta told a news conference that Barcelona, in its dealings with Negreira, had sought technical advice from "someone who has had a career in soccer".
"The advice does not constitute any kind of misconduct or criminal offence," he said.
Standing in front of a box in which he said that were 629 technical reports, 43 CDs and four aditional reports, Laporta said the professional advice was made with transparency and that invoices registered in Barcelona's accounting system had passed fiscal reviews.
"The Spanish Tax Department sent a letter to the Prosecutor's Office saying it could not prove that the payments to companies related to Mr. Negreira influenced the result of any match," he said.
Laporta also urged UEFA to be fair to Barcelona in its investigation.
LaLiga told Reuters on Monday it would not issue any comments regarding Laporta's accusations.
"The Nergreira case needs to be fully investigated by the proper authorities," it said.
Tebas said on March he had reported the case to UEFA because no punishment could be handed down under Spanish sports law since three years had passed since the alleged infringements.
Reuters has asked Real Madrid for comment on Laporta's remarks.
