The mother of missing teenager Gaia Pope has said she is "holding on to hope" after clothing belonging to her daughter was found on open land outside Swanage.
The case is now being treated as a murder inquiry.
Writing in the Find Gaia Facebook group, Natasha Pope said: "I believe in this community and I believe miracles can happen.
"I am holding on to hope, along with Gaia's sisters and the whole family who are my strength. Please hold on with us."
Police have said clothing discovered on Thursday on open land north of Swanage appeared to be Miss Pope's and matched what she was wearing when she was last seen.
Miss Pope vanished on the afternoon of November 7. On Friday night, volunteers were out with torches scouring acres of the Dorset countryside in an effort to find the 19-year-old.
So far, three people have been arrested on suspicion of murder.
A 49-year-old man named locally as Paul Elsey was released under investigation on Friday afternoon. A 71-year-old woman and a 19-year-old man were released under investigation on suspicion of murder on Tuesday following their arrest the previous day.
Volunteers are being asked to join mass searches of Swanage today. People are being asked to gather at midday at three separate locations to join line-searches.