"FC Sion have been informed that, on the afternoon before the game against Grasshoppers Zurich, information is said to have circulated in betting shops that the game would be manipulated and it would be better to gamble on the Zurich team," the club said in a statement on their website.
"This information has been handed over by Sion FC to the federal prosecution service," the club added. Sion lost last Wednesday's game 2-0.
"If the suspicion turns out to be well-founded, Sion will show a no-tolerance policy to any involved person.
"For the time being it is better not to jump to any premature conclusions."
German police said in November that they had dismantled a gang with more than 200 suspected members operating in nine European leagues.
Police in Germany, Britain, Austria and Switzerland cracked down on the ring, staging simultaneous raids that resulted in 15 arrests in Germany and two in Switzerland.
Officers seized one million euros in cash or goods as part of the investigation. The ring was reported to have tried to fix some 200 matches across the continent.
In December, UEFA president Michel Platini described match-fixing as the biggest scourge facing the game.
European football authorities say they are constantly monitoring matches for suspicious betting patterns.
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