Argentinian daily La Nacion has claimed that a government agent known only as ‘Agent G’ has been secretly following Messi around and keeping a close eye on his finances after he was named in the Panama Papers scandal, which broke last April.
More than 11 million documents were leaked from Panamanian law firm Mossack Fonseca showing how the rich and powerful around the world use shell companies registered in offshore tax havens to hide their wealth and avoid paying tax.
Following the exposé, Argentina’s president Mauricio Macri vowed to clamp down on any elite citizens involved in tax-dodging.
An Argentinian national, Messi was found guilty of three counts of tax fraud and depriving the Spanish tax authorities of €4.1m (£3.5m, $4.4m) between 2007 and 2009, by a Barcelona court in July 2016.
As a result, he and his father Jorge Messi were sentenced to 21-months in prison and fined around €3.5m for using tax havens in Belize and Uruguay to conceal earnings from image rights.
The pair deny any wrongdoing and have appealed to the Spanish Supreme Court to scrap their suspended sentence.
The appeal is scheduled to be heard this week.