The raids are linked to a probe into the transfer of Aleksandar Mitrovic from Anderlecht to Newcastle in 2015
The former general manager of Belgian football club Anderlecht, Herman Van Holsbeeck, has been questioned as part of a fraud inquiry on player transfers.
He was general manager of Belgium’s most successful football club for some 15 years, until last year.
Earlier this week, two were held as part of the probe into the £13m (€18m) transfer of striker Aleksandar Mitrovic from Anderlecht to Newcastle in 2015.
It is understood Newcastle believe they are not directly connected to the case.
Belgian federal prosecutors said an arrest was made on Thursday morning in relation to the case, without providing a name.
However, sources close to the investigation told AFP and Reuters news agency that Mr Van Holsbeeck was the one detained.
Meanwhile, Mr Van Holsbeeck’s lawyer told Belgian broadcaster RTBF he was not surprised at his client being questioned.
“It is logical that Herman Van Holsbeeck is heard after yesterday’s arrests over various transfers. My client being one of those responsible for transfers at Anderlecht at the time, it is logical that he can explain himself on this transfer in particular,” Daniel Spreutels told RTBF.
One of the people arrested this week was players’ agent Christophe Henrotay, while the other was said to be an associate in Belgium.
The investigation centres on alleged illegal payments made as part of Mitrovic’s moves from Partizan Belgrade to Anderlecht in 2013 and then from the Belgian side to Newcastle United, Belgian media reports say.
In April, Anderlecht premises were searched. No-one was detained at the time.
A separate inquiry into suspected fraud involving transfers during the 2017-2018 season led to raids on premises linked to Anderlecht, Club Bruges and Standard Liège last October.