A teenager was allegedly spat at by a man at a Stratford shopping centre after turning down his date invitation.
Police say they are investigating an allegation of stalking following the incident in December last year.
A 19-year-old woman reported she had been approached by a man in Westfield Stratford City who asked her on a date, which she refused.
She said the man then returned the following day and spat at her.
Detective Constable Marlon Caldwell said: "As a result of this man’s actions, the victim now completely avoids the shopping centre.
"No one should ever have to modify their behaviour because of the unwelcome actions of somebody else.
"Incidents of this nature are completely inappropriate and we are conducting a full and through investigation to bring the person responsible to justice."
Police have released an image of a man they want to speak to in connection with their investigation and ask anyone who recognises him to get in touch.
Anyone with information should call 101 or tweet @MetCC and provide reference CAD 3646/4Dec.
To remain completely anonymous, contact independent charity Crimestoppers via crimestoppers-uk.org/ or call 0800 555 111.
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