Real Madrid superstar Cristiano Ronaldo is facing possible charges of tax fraud in Spain. Prosecutors have passed a file to the country's tax office, which will decide whether to press charges against the Portuguese striker.

Reports in Spain say Ronaldo, 32, is suspected of defrauding 15m euros between 2011 and 2014.

In December, leaked documents suggested Ronaldo had avoided tax on income from image rights allegedly held in offshore accounts. He subsequently denied the claims.

Manchester United manager Jose Mourinho was also implicated in those claims -- published after an international consortium of journalists obtained a trove of about 18 million documents. He also denied the claims.

According to Cadena SER, Ronaldo held money earned from his image rights in the Virgin Islands, but he fully regularised his situation with the tax authorities in 2014, prior to any investigation being started. At that point the player paid six million euros of tax, which were paid in relation to the tax year 2014.

However, according to some of the tax inspectors, the player should have filed a complementary tax return for all the years involved, not simply lumping it all together in relation to 2014.

There is a second point of discrepancy between the inspectors, relating to a complex tax question of the classification of income. Ronaldo declared certain amounts as having been paid as image rights, while the tax inspectors believe it should have been treated as royalties, with a higher tax generally applying.

At the moment, the tax inspectors involved in drawing up the report are not in agreement on whether criminal proceedings should be started against the player or whether a simple administrative procedure would be appropriate. That decision will left up to the prosecutors.