British Transport Police said today a woman has come forward after a video emerged on YouTube appearing to show a female passenger telling a black man "you guys used to be slaves".
The video, which has been watched more than 500,000 times on YouTube, shows a male and a female passenger rowing on a Jubilee Line train to Stratford.
The woman then appears to tell the black passenger "people have a problem with you guys" and "you guys used to be slaves", before other passengers start telling her to "shut up".
Police launched an investigation and appealed for witnesses to come forward after the video was posted online last week.
Officers said they will now interview the woman, who is from Essex, but they are still searching for the person who made the video. Anyone who saw the incident is asked to call British Transport Police quoting the reference T/B11.