Hilary Foster has described her eldest daughter Hannah as "everything you'd hope for".
"An absolutely lovely daughter, just always so cheerful, huge smiley face. She had lots of friends and was really enjoying life," Mrs Foster said.
Hannah Foster was 17 when she was murdered.
She was abducted less than five minutes walk from her home by 41-year-old Maninder Pal Singh Kohli, who has been convicted at Winchester Crown Court in Hampshire of raping and murdering her.
He raped Hannah in his van and then strangled her.
Hannah was absolutely totally unable to deal with the threat of violence, she would have just turned to jelly
Afterwards he dumped her body in undergrowth near a railway bridge in Southampton's West End.
Earlier that evening, Hannah had been out with friends to the Hobbit pub in Bevois Valley in Southampton, a popular student hangout.
Mrs Foster said she did not expect her to be out late as she was tired from going to a friend's birthday party the night before.
Recalling the last moments with her daughter, she says: "I didn't even give her a kiss goodbye.
"It was just one of those things where you think she is just popping out for an hour or so.
"She just called from the hall and said: 'Bye mum' and I just said: 'Bye, see you later'.... I wish I'd given her a hug."
A-level student Hannah was due to study medicine at university
Hannah was an A-level student at Barton Peveril College in Eastleigh, Hampshire, and had secured a place to study medicine at two universities.
It is nearly six years since Hilary and Trevor Foster lost their daughter, on 14 March 2003.
When they saw her lifeless body in the mortuary they made one last promise.
"You feel as though you failed her as parents," Mrs Foster said.
"You are here to protect your children and seeing her [in the mortuary]... You just think how could this have happened? We're caring and responsible parents.
"It was just an overwhelming emotion of pain, absolute pain, that someone could do this to your beautiful daughter.
"I remember talking to her and saying, 'We'll find who did this to you'. And that's what we've been focused on doing since."
In July 2004, they travelled to India with Hampshire police officers to make media appeals and publicise a £70,000 reward and telephone hotline - all in an attempt to trace Kohli, who became the prime suspect within days of the murder.
The Fosters appeared on Crimewatch and Indian television to trace Kohli
Kohli was finally extradited to the UK in July 2007 to face trial for Hannah's murder.
Mrs Foster, who works as a hospital nurse, remembers her daughter as a "very generous girl".
"Hannah had a real zest for life," she said.
"She put her mind to something and was just so committed to what she was doing and she was so protective of Sarah (her sister).
"She was great fun to be with, great sense of humour, very, very clever girl who found academic work an absolute breeze."
Mr and Mrs Foster said they would never be able to forgive Kohli.
"I envy people who are able to forgive in circumstances like this, because there's no way I'll ever forgive him," Mr Foster said.
"I can forgive someone for stealing some property. I can forgive someone for crashing into my car. I can't forgive anyone for killing my daughter.
"How dare someone act as God in the decision when my daughter should die," Mr Foster says, his voice trembling.
Mrs Foster continues: "It wasn't all over quickly for Hannah. We know that he was with her for quite a long time.
"He would have known what sort of girl she was and that, to me, makes it even more disturbing.
Hannah was very generous and "always had a smile on her face"
"She was the proverbial lamb to slaughter, she would have shown her fear. Some 17-year-old girls are feisty. They would have been screaming, they'd have kicked out, they'd hurled abuse at him, they'd have made it really hard for him.
"But Hannah was absolutely totally unable to deal with the threat of violence, raised voices, she would have just turned to jelly.
"I knew my daughter so well, she'd have had nothing left to fight with. That's what tortures us, she just did not even have a chance."
Mr and Mrs Foster said it was only after Kohli was convicted that they could properly start to grieve for their daughter.
"The focus has been on her killer, not on Hannah," Mrs Foster said.
Her husband added: "I don't think there is such a thing as closure.
"It doesn't go away, the grief and the pain, they're going to be there until the day we die."
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