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.

Last 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.

Detectives said that clothing found on Thursday on open land north of Swanage matched what the teenager was wearing when last seen.

Members of the public have joined the hunt, distributing hundreds of missing person posters, as a large social media campaign has been launched to find Miss Pope.

Miss Pope's father, Richard Sutherland, fears her epilepsy may have played a part in her disappearance as she had been warned by doctors that she was at risk of sudden death from the condition.

Mr Sutherland said: "The doctors have said that she is at risk of sudden death from epilepsy, or sudden epileptic death. It's pretty serious.

"One thing we've really tried to do is not to go off down every speculation because that can lead you to 100 different ideas with a 100 different variations on everything.

"But, it's entirely possible that her epilepsy has played a big part in this and that's meant it's been more difficult to find her."