The phone of a 16-year-old missing for almost a week was switched off two hours after she was last seen.
Fears are beginning to mount over the welfare of Louise Smith, with senior investigators sending a personal plea to the teenager to come home.
Detectives managed to trace a signal from Louise's mobile phone to Emsworth skate park near Havant, Hants.
Since then the device has been turned off and there have been no sightings of the teenager.
Detective Inspector Ron Lock, who is now leading the search for Louise, said: "I want to appeal to Louise directly to get in touch with us.
"Louise, it has almost been a week since you went missing and our priority is to know that you are okay and safe. Please call us or a loved one, so that we can help you."
Louise disappeared at around midday on Friday and has not been in contact with anyone since.
Worried friends and relatives have set up a website for people to share and leave messages, as well as helping to co-ordinate the local search for her.
A post on a community Facebook group dedicated to finding Louise said: "Louise is part of a missing child investigation, headed by Hampshire Police.
"The country is in crisis and we remain on lockdown. We ask at this stage that you respect the police who have not requested the public to do their own searches.
"They have asked if you have information to contact them.
"They are in the important part of their search, the police are the experts at this stage. Please refrain from doing your own searches it will hinder the police.
"When they require the public to search they will request this, we are here to raise awareness.
"Louise is missing, we are not here to overwhelm Louise or worry her. Please, if you sight Louise please do not approach her, it may scare her, please dial 101."
Her family speculated that the girl was not going to switch her phone on, knowing that the police are able to trace her.
The last reported sighting of Louise was in Somborne Drive, Havant and she was thought to be wearing black jeans, a black and white striped tee-shirt, black trainers and a black coat with a fur hood.
A picture released by her family to assist in the investigation showed her in a teal dress with an intricate headpiece dangled over her hair and earrings, which was an outfit it was believed she had worn to her school prom.
She was described as white, around 5ft 2ins tall, of slim build and with straight, black, shoulder-length hair.
A spokesman for Hampshire Constabulary said today: "Louise, aged 16 years, was last seen at around midday on Friday May 8 in Somborne Drive, Havant.
"She has not been in contact since Friday and her family are growing increasingly concerned for her welfare, as are we.
"Officers have been following several lines of inquiry since Louise was reported missing and we are keen to hear from members of the public who may have seen her."
