The World Player of the Year and his father Jorge allegedly filed fraudulent tax returns for the years 2006, 2007, 2008 and 2009, according to a spokesperson for the prosecutor's office for tax crimes in Catalonia.
A Barca spokesperson did not immediately respond to a request for comment.
Messi, who will be 26 this month, is one of the world's highest-paid athletes with a salary of just over $20-million a season, according to Forbes magazine.
On top of his Barca wages, he pulls in around $21-million in endorsements from sponsors including Adidas, Pepsi and P&G and he is 10th on Forbes' latest list of top-earning athletes.
Messi came on for the final half-hour of Argentina's World Cup 2014 qualifier against Ecuador in Quito on Tuesday which ended in a 1-1 draw. – Reuters