Reports in Spanish newspaper Marca, confirmed that former Real Valladolid striker Borja Fernandez, who was arrested on June 7, has been released by police investigators, due to a lack of evidence against him.
He had originally been arrested following betting irregularities around Valladolid's final game of the 2018-19 La Liga season, where they lost 2-0 to Valencia CF.
Former veteran La Liga forward Carlos Aranda is still under investigation however.
Aranda remains central to the investigations, with potential links to Lazio forward Ciro Immobile and Mattia Mariotti, now being looked into.
Marca claims police are looking into phone conversations between Aranda and Mariotti.
Immobile is not believed to be being investigated directly, but the suggestion is that the Italian international is a member of an illegal gambling club.
The final allegation into Serie A looking into Aranda and Mariotti potentially fixing games involving the recently relegated Frosinone CF.