UEFA officials are investigating whether the first leg of the Champions League group-stage matchup between Hapoel Tel Aviv and German club Schalke was manipulated by players on the pitch.

Allegations of fraud and match-fixing reached UEFA, which is considering whether the unusual volume of bets placed on the match may have affected the game's outcome.

According to the German newspaper Sueddeutsche Zeitung, UEFA investigators are looking into a series of large-scale bets totaling 12 million euros, which were placed with an Asian gambling syndicate. The bettors were pinning their hopes on Schalke to defeat Hapoel Tel Aviv. The German side won the October 20 match 3-1.

Schalke coach Felix Magath told German newspaper Bild that he did not notice any unusual activity during the home match against Hapoel. UEFA released a statement saying that it expects the investigation to conclude within days.

German media reports said one possible focus of the investigation is former Hapoel defender Douglas da Silva. The Brazilian played poorly in the match against Schalke. In Israel, da Silva is an alleged victim of an extortion plot hatched by a former teammate at Hapoel Kfar Sava, Liron Zarko, and his father, Shlomo Zarko.

The Zarkos stand accused of trying to extort hundreds of thousands of shekels from da Silva by threatening to release embarrassing photographs of the defender if he refused to comply. Shlomo Zarko, who is currently under house arrest, denied the charges. He maintains that da Silva owes his son $20,000. He also claims that his son sought to obtain the money before the Brazilian departed for Austria to join his new club, Red Bull Salzburg.

A face-to-face confrontation between Liron Zarko, who is also in custody, and da Silva recently took place, though the results were not immediately available.