West Ham probe Arthur Masuaku's £6m summer move from Greek Champions Olympiacos

West Ham have launched an investigation into the £6.2million deal that saw Arthur Masuaku move to the club from Greek champions Olympiacos in the summer. 

Senior club officials are concerned they have overpaid by almost £1m for the 22-year-old and sent a representative to Athens last week to establish if that is the case. 

The Hammers are trying to ascertain whether someone has been paid who was not declared on the official transfer document. 

It is believed the club hierarchy want to satisfy themselves that the transfer business was conducted properly at both ends of the deal.