Antonio Rudiger, the German international defender who was subject to a stream of monkey chants in Chelsea's Premier League win over Tottenham, said he wants the culprits caught and punished.
The 26-year-old was targeted by some Tottenham fans after he was involved in a clash with Son Heung-min that triggered a red card for the South Korean star.
Son kicked out at Rudiger after they collided and the German centre-back went to the turf clutching his stomach.
"It's just such a shame that racism still exists in 2019. When will this nonsense stop?," Rudiger tweeted.
"I really hope that the offenders will be found and punished soon, and in such a modern football ground like the Tottenham Hotspur Stadium with dozens of TV and security cameras, it must be possible to find and subsequently punish them.
"If not, then there must have been witnesses in the stadium who saw and heard the incident."
"I don't want to involve Tottenham as an entire club into this situation as I know that just a couple of idiots were the offenders."