The Spanish league is investigating match-fixing involving a game between Rayo Vallecano and Real Sociedad.

League president Javier Tebas told Spanish radio Cadena SER on Friday that the league is investigating Rayo's 2-1 loss at Sociedad on Sunday.

Tebas said the league decided to launch a probe after it noticed ''abnormal'' movements in the betting market for the match and heard ''rumors of an argument between players at halftime.''

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Rayo's players, coach and president denied there was any wrongdoing.

''This isn't good for us or the club or the league,'' Rayo captain Roberto Trashorras said. ''I don't know who wants to hurt Rayo, but these are very strong allegations. These things have to be proven.''

The loss left Rayo in the relegation zone with one match left.

Rayo must beat already relegated Levante on Sunday and hope for favorable results in other matches to stay in the first division. Sociedad was in the middle of the table before the match and not in the relegation fight.