Former Barcelona president Joan Laporta is defending Lionel Messi against allegations of tax fraud, a case that experts say could carry a prison sentence for the Argentina star.

A Spanish state prosecutor filed a fraud complaint on Wednesday alleging that Messi and his father Jorge avoided paying 4 million euros ($5.3 million) in back taxes through illegal overseas tax havens.

Laporta told Cope radio he is ''convinced that they have not committed any irregularity.''

Laporta's presidency coincided with the period the complaint covers from 2006-09.

If found guilty and barring an out-of-court deal with the tax office, Messi and his father could face 2-6 years in jail, according to Professor Sandalio Gomez, a sports finance analyst at the IESE Business School.

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