Police have been searching through woodland near a railway station in Essex where a missing 17-year-old is believed to have disappeared.
Teenager Natasha Coombs, from Dovercourt, went missing on Friday
Natasha Coombs was travelling back to her home in Dovercourt, Essex, from Ipswich, Suffolk, when she disappeared last Friday night.
Police say Natasha was seen boarding a train at Ipswich.
She was due to switch trains at Manningtree but this is where her phone disappeared from the mobile network.
Police said there were no cameras on the train and the cameras at Manningtree station were not working.
Police said a signal from her mobile phone had been traced to a transmitter near to Manningtree station, where Natasha should have changed trains to travel home.
Insp Adrian Dearsley said on Friday night: "I am still hopeful of finding Natasha but as time goes on we must look to the possibility of finding a body."
Search teams combed woodland near Manningtree station in Essex
Pc Heather Alston, a police search adviser working on the investigation, said: "We are dealing with a young girl who has effectively disappeared from the face of the earth, which is very concerning.
"It's unusual for a teenage girl to go missing like this.
"There's an awful lot of work being done to find clues. It's a very distressing time for her parents so we need to give them as many pieces of information as we can."
Search teams have yet to find Natasha's mobile phone, which was last used in Manningtree at about 2315 BST last Friday.
It is understood a call was made from the phone moments before it was switched off.
Officers looking for Natasha, who had been on a night out with friends in Ipswich, were concentrating their search on the area surrounding Manningtree station.
Manningtree is around nine mile from Ipswich and Natasha was expected to change there for a train to make the further eight mile trip to Dovercourt near Harwich.
On Thursday, Natasha's parents, Gary and Joanne, made a plea for help finding their only child.
Mr Coombs, 48, who works in Norwich, spoke of the "unimaginable pain" he and his 40-year-old wife were suffering.
The family were due to go on holiday on Saturday.
Natasha is described as white, 5ft 3in and slim with brown highlighted hair.
When last seen she was wearing a purple sequined top, a purple, pink and white skirt, a white jacket and pumps.