The BBC reports that a missing 14-year-old girl from Margate is thought to be with a 48-year-old man, either in the UK or in Spain.
Nataleigh Cross, of Caroline Square, has been missing since 5 July.
Kent Police said it was now established that she had become friends with Peter Willcox, of Northdown Road, Margate, and also that her passport was missing.
A police spokesman said Mr Willcox, who has Spanish connections, could not be traced: "It is possible that they may be together abroad, possibly in Spain."
He said the force was liaising with Interpol and the Spanish Police.
Det Insp Dean Edwards said: "We would urge Nataleigh to get in contact with us as soon as possible.