Police say they have still not given up on finding a young woman alive over three years after she vanished.
Leah Croucher, then 19, was last seen by her family on Valentine's Day 2019 and there has been no confirmed sightings since.
She was reported missing from Emerson Valley, Milton Keynes the next day after she failed to turn up to work.
But police say they are refusing to give up hope and have not ruled out that Leah, who would now be 22, is still alive.
The case's Senior Investigating Officer DCI Andy Howard says the force have not upgraded their investigation to a murder enquiry and have no plans to.
He told The Sun that the force is still "absolutely committed to finding Leah" alive.
“Despite previous appeals we have so far been unable to establish the identity of this female and so if you believe this was you or you know who it is, please contact the police," the officer said.
“We remain absolutely committed to finding Leah and seeking answers for her family.
“We continue to keep in close contact with Leah’s family, and continue to support them.”
The last confirmed sighting of the teenager was at 8.16am on CCTV in Furzton the morning of February 15 and the last activity on her mobile was just after 8.30am the same day.
Leah's devastated family also shared an emotional statement in February, saying the public is "our only hope" in finding her and have vowed to never stop looking for answers.
Police released a new image from Furzton Lake, which shows a figure of a person dressed in black from the day Leah disappeared.
It is not clear if it is Leah, but the image also shows members of the public, who the police would like to speak with to help with their investigation.
Police have said that the images released today give them "real optimism" in their investigation.
Detective Chief Inspector Howard said earlier this year: “The image we are releasing today is not of a high quality, but I am hoping that somebody will recognise themselves as being in this picture."
He said in February that he is particularly keen to speak to a dog walker who was seen in the area at the time of Leah's disappearance.
The family's statement told of their anguish following the disappearance of their 'treasured' daughter.
It read: "It has been three long, desolate years since our beautiful and wonderful daughter Leah, vanished without a trace on her way to work.
"We still have no answers as to why. No clues as to what happened. No idea as to where or how she is.
"It is impossible to stay positive after all this time, it was difficult at the start of this, but now, the task is so futile, our lives are so bleak.
"It is harder each day to tell ourselves that today will be the day that we get answers, today we find out what happened three years ago. Today we get our treasured daughter back.
"It is unimaginable to convince ourselves that this is not a lie we tell ourselves so that we get out of bed each day. Each day is torture.
"Each day feels like an eternity of pain and despair.
"Each time the phone rings or there is a knock at the front door, our hearts still leap in our chests.
"That familiar surge of hope springing up in our throats. That familiar wave of despair that crashes over our very souls each time."
