Lorenzo Sanz, who was president of Real Madrid from 1995-2000, has reportedly been arrested by police in the Spanish capital.
El Pais state that he was detained by Spanish police in the Retiro district of Madrid, due to his allegedly being involved in fraud earlier in the decade.
After being questioned by the police, Sanz was released.
It is also reported by Marca that Sanz was arrested after an undercover policeman organised a meeting with the former president, at which he claimed there would be an exchange of promissory notes.
It is reported that the police were investigating the alleged payment of €7.5 million in works of art in 2005, which the former Real Madrid president would have used to buy Italian side Parma.
However, the buyout fell through in January 2006 and El Pais believe that Sanz then lost the money, which had been paid in advance.
This is not Sanz's first brush with the law: in 2008 he was formally accused of fraud. He is also undergoing financial difficulties, having had his Marbella home claimed by creditors in April this year.