LaLiga has filed a complaint with Spanish authorities after former player Aday Benitez said he was offered a bribe to lose a second division game while on the books of Girona.
Benitez, 35, retired from the game in the summer of 2021 after spending seven seasons at Girona.
The former Spanish winger said: "In football, there were briefcases, hidden payments... They have personally offered me that, and I have not accepted them.
"They offered me close to €50,000 to lose a game. It was absurd to accept because that year we were promoted to the First Division. We had one league game left. I was not going to stain the season for a league game."
Girona gained direct promotion to LaLiga for the first time in the club's 87-year history in the 2016-17 campaign after finishing second in the standings behind Levante.
Benitez also described the modus operandi of the alleged match-fixing scheme.
"They contact a player to connect with trusted people in a locker room," he said. "You only have to catch three, but more have to take part. As long as you buy a goalkeeper, a central defender and a striker, you practically have it done. But you can't buy just three players, clearly."
LaLiga said in a statement it had reported Benitez's revelations to Spain's national police centre for Integrity in Sports and Gambling (CENPIDA) and added: "LaLiga Integrity and Security area has as one of its objectives the prevention, detection and reporting of any conduct that infringes 'fair play' and could adulterate the competition.
"The predetermination of results is a crime, as well as proving the sole intention of fixing the proposal."
The fixture in question is Levante's 8-0 first round win over Huracan Melilla, which was played on Dec. 2, 2021.
LaLiga has worked in recent years with law enforcement and technology experts to ensure that matches are free from corruption as well as giving educational workshops to players to prevent match-fixing.
While the number of cases of match-fixing in professional football has significantly fallen, last month, LaLiga confirmed an investigation is underway regarding a possible case of match-fixing during last season's Copa del Rey.