Detectives investigating the disappearance of 15-year-old Maddie Thomas are now treating the case as child abduction.
Maddie has been missing since the Southmead area of Bristol since Tuesday, 26 April and officers believe she is likely to be with a man.
Detective Inspector Laura Miller said: “We are no longer investigating Maddie’s disappearance as a missing person case but as a child abduction.
“When Maddie has previously gone missing she has been found in the company of adult men and it is mainly due to this history that we believe she is likely to currently be with someone.
“Maddie is a child in foster care, no one has permission to keep her from her carers. She is vulnerable and at risk of being taken advantage of.
“We’re really concerned about her safety and have a dedicated team working extremely hard to locate her.”
DI Miller added: “No one has seen or heard from Maddie for 15 days – since she saw a relative on 26 April when she said she was going to the shop.
“The circumstances of her disappearance are deeply worrying for us; her family and her carers.
“We have a number of lines of enquiry and while we’ve had great deal of help from the public to date for which we’re incredibly grateful, we still need more.”
“But Maddie could be anywhere in the country and so we really need our appeal to be shared and reported on as widely as possible.
“We’re asking anyone who sees Maddie to call 999 immediately and anyone who speaks to her or sees her online to call 101.
“Maddie – if you see this please contact us if you can to let us know you’re safe. Everyone is worried about you.”