A seven-year-old girl missing for more than a year may have been spotted in Sussex.

The sighting follows an appeal earlier this week by the girl's mother Marcela Alvarez for the return of her daughter Esmeralda.

She was abducted in July 1999 by her father, 62-year-old Edgardo Alvarez, a former Spanish lecturer at Crawley College, during an access visit.

Phil Woolf, spokesman for Forest Division of Sussex Police, said: "We are following up one line of inquiry. It was a sighting in Sussex. Someone saw a man and girl last Sunday who appeared to be same people in the photographs."

Police are not revealing the precise location of the sighting in case it hinders their investigation.

One theory is the child and father may still be in the Sussex area. The little girl disappeared after her mother took her to meet her father at Victoria Station. It was the second time Edgardo had taken her.

In 1998 he took Esmeralda to America while her mother was visiting Mexico with her own mother.

Esmeralda, sometimes called by her first name of Jasmin, was born in Crawley and lived with her family in Northgate and then in Gossops Green.

Her parents are Mexican and she speaks English and Spanish.

She was a pupil at Our Lady Queen of Heaven Primary School in Northgate until 1998, when, following the break-up of her parents' marriage, she moved with her mother to London.

Marcela won custody and had been planning to take her back to Mexico.

It is believed Edgardo, who remained in Crawley, could not bear the thought of his daughter leaving the country.

He was due to return her to Crawley police station but failed to turn up.