Rachel Wilson, 19, was last seen 13 days ago and friends and family say it is "completely out of character".

More than forty police officers have been assigned to the case and an incident room has been set up at a police station in the town.

Ms Wilson - who was last seen at 2330 BST on 30 May - is the third prostitute to go missing from the town in the last four years.

'Concern in town'

Donna Keogh, 17, vanished from Hartington Road in Middlesbrough in April 1998, after reports she was seen getting into a red hatchback car.

Her disappearance was re-examined after 21-year-old prostitute Vicky Glass was murdered in 2000.

Detective Superintendent Tony Hutchinson, who is leading the investigation into Ms Wilson's disappearance, said police were not linking the three cases.

Mr Hutchinson is appealing to clients of Ms Wilson

He told BBC News: "I am mindful of these inquiries, but at this moment in time I am not linking these inquiries to Rachel's disappearance.

"There's no doubt there will be some concern, regards to the prostitutes in the town, but I would like to stress that this is a missing from home inquiry at the moment."

Mr Hutchinson said Ms Wilson was a known heroin and crack cocaine user.

The police are hoping drug dealers and clients will come forward if they have any information.

Marylin Surtees, manager of a drop-in centre for prostitutes in Middlesbrough, told BBC News Online that she was extremely worried.

"Donna Keogh is still missing and the killer of Vicky Glass has still not been found. It's really, really worrying.

"I think it is possible that they could be linked and all the other working girls are very worried about it."