Vinicius Junior's Real Madrid future has been repeatedly called into question amid links to the cash-rich Saudi Pro League.
The league has analysed images and utilised lip-readers to identify those responsible for the alleged racist abuse.
The Brazil international's current terms run until 2027 with talks having begun last month over extending them.
Real Madrid head coach Carlo Ancelotti has provided an insight into the reasoning behind his decision to haul Vinícius Jr.
Vinícius Júnior has said he wants to renew his contract at Real Madrid "as soon as possible" despite ongoing links with a big-money move to Saudi Arabia.