The league has analysed images and utilised lip-readers to identify those responsible for the alleged racist abuse.
Barcelona has cruised to a 4-0 rout of 10-man Real Sociedad to regain the Spanish league lead. Gerard Martín, Marc Casadó, Ronald Araujo and Robert Lewandowski scored a goal each to put Barcelona one point ahead of second-placed Atletico Madrid.
Barcelona reclaimed top spot in La Liga with a comfortable victory over 10-man Real Sociedad. Atletico Madrid had leapfrogged them following their 1-0 win over Athletic Club on Saturday.