The ex-chairman of English Premier League club Watford has been charged and called to appear in court in Spain in relation to tax fraud involving second-tier club Granada, the court handling the case said Friday.

The Italian Raffaele Riva is suspected of involvement in "presumed irregularities" committed by former Granada president Enrique Pina and ex-club owner Gino Pozzo "as well as the companies and clubs linked to them)", the examining magistrate said in his ruling.

These clubs include Italian side Udinese, Granada and Watford.

Pina and Pozzo, who owned Granada before selling the Andalusian outfit to Chinese investors in 2016, had already been charged with tax fraud and alleged money laundering in the period from 2013 to 2016, the investigating magistrate wrote.

The magistrate has now decided to pursue Riva for his alleged involvement in the affair, notably for running a company belonging to Pozzo and based in Spain.

Pozzo is the owner of Watford and the son of the owner of Udinese in Serie A.

"Apparently the three clubs form a commercial triangle in which the revenue generated from player sales is hidden from the respective tax authorities and goes to a holding company in Luxembourg," the magistrate's decision said.

Riva stepped down as executive chairman of Watford in November 2016 following allegations in a British newspaper that the club forged a letter from HSBC bank during Pozzo's 2014 takeover of the club, which was bought by his family in 2012.

Pina, who moved on to become the managing director of Spanish second-tier side Cadiz, has been remanded in custody after being arrested last month.