Milan prosecutors are looking into last year's 1.2 billion euro ($1.3 billion) sale of AC Milan to U.S. private equity fund RedBird Capital from U.S. fund Elliott, a judicial source said on Thursday.

Confirming earlier Italian media reports, the source said Italy's tax police are requesting documents from accountants and advisers involved in the deal, adding that no specific people or companies were under investigation.

The probe, which revolves around alleged embezzlement, originates from a complaint by Blue Skye Financial Partners, a minority investor holding an indirect stake of 4% in the Serie A club, the source said.

Blue Skye had previously accused Elliott of violating its rights by engaging in "behind closed doors" talks to clinch a sale of the seven-time European champions and it has challenged the deal also in Luxembourg and in the United States.

Elliott, which took over the club in 2018, billed Blue Skye's legal actions as "frivolous and vexatious", meaning it believes they have no reasonable basis in fact or law.

RedBird and Elliott had no immediate comment when contacted by Reuters on Thursday, while Blue Skye did not respond to a request for comment.

AC Milan, who last year won the Serie A title for the first time in 11 years, are currently second in the league. They were for a long time owned by media magnate and former Italian Prime Minister Silvio Berlusconi, who sold the club in 2017.