Police in the Brussels borough of Anderlecht purchased 48 bikes from Mr Merckx's bicycle company, but there are now reports that a police officer tipped off Mr Merckx about the price rivals were going to charge.
The investigation started in 2006 after the local Anderlecht force purchased 48 bikes from Mr Merckx's bicycle company Eddy Merckx Cycles. At the time the five-times-winner of the Tour de France headed the business.
At least one police commissioner stands accused off tipping of the cycling legend about rival tenders. In this way Eddy Merckx Cycles was able to draw up an interesting tender of its own and land the contract.
The officer who tipped off Mr Merckx is thought to have been given a discount on the purchase of a bike.
Several police officers have already been named as suspects in the case.
Sven Mary, who is representing several police officers, told the VRT: "It's a case of passive and active corruption. It’s a very diverse case. Bicycles are involved but also sports clothes and police vehicles. More is involved than the bicycles ordered by Anderlecht police.”