Former Spanish refereeing committee (CTA) vice president Jose Maria Enriquez Negreira threatened to expose Barcelona in 2019 after the Catalan club stopped making payments to his company, according to a burofax document published by El Mundo newspaper on Friday.

Negreira is being investigated by the Spanish prosecutor's office for receiving at least €1.6 million from Barca between 2016 and 2018 for consultancy work.

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El Mundo has revealed that the burofax, which Negreira sent in February 2019 to then-Barca president Josep Maria Bartomeu, threatened to reveal alleged irregularities of the club unless their partnership resumed.

Barca stopped making payments to Negreira's part-owned company DASNIL 95 SL after June 2018 once Negreira was no longer vice president of the CTA.

According to El Mundo, Barca paid a total of €6.65m without tax to Negreira's company, with payments dating to 2001 when Joan Gaspart was club president.

The following club presidents reportedly continued those payments and even increased the amount.

On Wednesday, Barca said in a statement that the service contracted from Negreira's company, among other things, was for "technical reports related to professional refereeing" and that such practice was commonplace in football.

LaLiga president Javier Tebas responded on Thursday and said the club will not face sporting sanctions over the Negreira revelations because statute of limitations laws in Spain make it possible to punish clubs only within three years of any offences.

About the accusations, former Barcelona president Josep Maria Bartomeu told La Vanguardia: "It is false and absurd to think that we paid off any referee."

ESPN asked Bartomeu for comment Friday regarding the alleged threats from Negreira reported in El Mundo.