The family of missing teenager Gaia Pope has vowed to find their "darling girl", as police released a man and a woman under investigation.
The 19-year-old has not been seen for almost a week, and Dorset Police had arrested a 19-year-old man and a 71-year-old woman, who were both known to Ms Pope.
She was staying at an address in Swanage, and was last seen in the town on the afternoon of November 7.
Dorset Police Detective Chief Inspector Neil Devoto said the "believe that she may have come to harm".
Det Chief Insp Devoto continued: "It has been almost a week since Gaia's last confirmed sighting and she has not been seen or heard from since.
"We have looked through CCTV that covers the Swanage area, including transport hubs, and there is nothing to suggest she has left the area.
"Her disappearance is completely out of character and, following our extensive inquiries, we sadly now believe that she may have come to harm.
"We have not yet found Gaia and our searches will continue.
"I would appeal to anyone who has information about her disappearance to please contact Dorset Police.
"Our specially-trained officers have updated Gaia's family and are supporting them at this very difficult time."
Releasing a statement through Dorset Police, the teenager's loved ones said: "The thought of seeing the sunshine of your smile again soon keeps us all going and hoping."
We want to express our deepest gratitude to the police, other emergency services and the huge numbers of volunteers and well-wishers. The massive effort to find Gaia has been a great comfort in what everyone will understand is a deeply worrying and scary experience for all who love Gaia so deeply. We understand that the police continue to investigate all possible scenarios, and we want to emphasise that the search for Gaia continues. We will be releasing information on the Find Gaia Facebook page regarding further volunteer search support. Please understand that we want to keep social media to constructive and positive efforts to find Gaia and not to encourage uninformed speculation which can have a negative impact on the family and be a distraction.