Shelley Pratt vanished on the way home from school five weeks ago.
She was last seen talking to an unknown man.
She was still in school -trousers and a purple hooded top with an I Love London slogan.
After talking to the mystery man, who also approached other women in the centre of Croydon, South London, -her Oyster travel card was used on another bus.
Shelley is described as 5ft 7in, brown haired.
She's had absolutely no contact with friends or family since her disappearance and it is possible that she may be with someone, perhaps in a house or a flat.
More top news
Resham Khan suffered 'life changing' injuries when she had acid thrown at her through the window of her car
Around 20 households are still in the blocks this morning and are now being told they 'must leave' over fire safety fears
The London grime star called for the Government to be 'held accountable' over the disaster