Demi was last seen at 11pm on Saturday (August 3) when she went to bed at a relative’s house in the Woodthorpe area.
North Yorkshire Police today said she may be in Leeds and could be using the train network to move around.
The force previously said that Demi has links to the Catterick and Harrogate areas and visited Scarborough with her family the day before her disappearance.
A police spokesperson added that the British Transport Police have joined the search.
“Please continue to report information and possible sightings of Demi as soon as possible,” they said.
Demi is described as black, slim build, 5ft 2ins tall, with reddish-black hair and brown eyes.
Police do not know what Demi was wearing when she went missing.
Anyone with information that could help find Demi is urged to call 101, select option four and speak to the Force Control Room.
Officers urge anyone that sees her to dial 999.
Quote reference number 12240139759 when providing details.
