The parents of a 25-year-old woman who has been missing for six days from her home in Bristol fear their daughter has been abducted.
Joanna Yeates, a landscape architect, has not been seen since last Friday when she went to a pub with colleagues.
Her mother Teresa Yeates said: "My little Jo, come back - whoever's got her, don't keep her - give her back."
Miss Yeates is thought to have returned to the Clifton flat she shares with 27-year-old boyfriend Greg Reardon.
Her father David Yeates said: "I think she was abducted after getting home to her flat.
"I have no idea of the circumstances of the abduction but because of what was left behind in the flat we feel she wouldn't have gone out by herself leaving those things behind."
Det Ch Insp Gareth Bevan, from Avon and Somerset Police, said Miss Yeates bought a Tesco Finest tomato, mozzarella and basil pesto pizza on her way home but there was no trace of the pizza, the wrapping or the box in her flat.
"We believe Jo reached her home address shortly after 8.30pm on Friday evening," he said.
"From CCTV, we know she bought a pizza at Tesco Express in Clifton Village.
"I believe she went back to her flat and that is because we found within the flat her coat, her mobile phone and her keys but what we have not found is any evidence of this pizza."
He said the pizza could provide a vital clue.
Police officers and mountain rescue teams spent much of Wednesday scouring cliffs and woodland around the Avon Gorge for any sign of the missing 25-year-old, who is originally from Hampshire.
'Going through hell'
Mr Yeates said his daughter had plans for Christmas and he did not believe she had simply gone away.
"She had plans to finish her Christmas shopping, then do some cooking and baking for when her friends were due to come round.
"Her and Greg were devoted to each other. She had all the space she wanted, no work worries, no money worries, nothing that was worrying her.
"If she chose to go away she would have taken some of her things with her like her purse and phone. I never thought for a second she would ever leave of her own volition."
Mr Reardon was visiting his family in Sheffield at the weekend and had not been able to contact his girlfriend.
"It's not the first time Greg has gone away or anything like that," said Mr Yeates.
"She does her own thing at the weekend and keeps in touch with Greg."
But Mr Yeates said his daughter did not always answer her phone so it was not totally out of character for Mr Reardon not to hear from her while he was away for the weekend.
"Concern was raised after Greg got back home and after waiting a couple of hours when there was no sign of Jo," he said.
Mrs Yeates added: "I don't think anyone close to her would be involved in her disappearance.
"If, for some reason, she had collapsed or been discarded, with all the snow and cold I can't bear the thought of it. I can't cope with it."
Mr Yeates said he needed to believe his daughter was still alive.
He said: "She had so much life in her. If it turns out she isn't (alive) I still want her back. We still want to hold her one last time."
In a message to his daughter, Mr Yeates said: "Please come home Jo. Our hearts are breaking up with not having our little girl with us. Greg is going through hell.
"Please contact us, we don't know what to do without you.
"If she's dead, please tell somebody where she is. We want her back whatever."