The hunt is on for a Chelsea fan who is said to have made a racist gesture against rival forward Son-Heung-min.
Chelsea are investigating alleged racist abuse directed at Tottenham player Son during Sunday's 2-2 draw with Tottenham.
The South Korean forward started the London derby and played 79 minutes before being replaced by Yves Bissouma.
The incident is believed to have taken place in the second half when Son went over to take a corner at the Shed End.
Footage shared by a football fan on Twitter appears to show a man pulling up the corners of his eyes - allegedly a racist jibe at Son's Korean ethnicity.