Barcelona and two of the club's former presidents are facing questions over alleged payments to a company owned by a former vice-president of Spain’s referees’ committee.
The focus of the inquiry is reported to be payments of €7.3 million made by the club between 2014 and 2018.
A judge must yet decide whether to take up the case.
Barcelona have not publicly commented on Friday’s development, but last month denied wrongdoing.
A statement said they had paid an external consultant for "technical reports related to professional refereeing", arguing it was common practice in the game.
On Tuesday, current Barca president Joan Laporta said: "Barca have never bought referees nor influence. That was never the intention and that has to be clear. The facts contradict those that are trying to tell a different story."
