A friend of 17-year-old Hannah Foster has described how they waved goodbye to each other after a night out.
Winchester Crown Court heard that Helen Wilkinson was the last person to see Hannah alive on 14 March 2003.
Miss Wilkinson described how Hannah watched her get on a bus, then waved to her, before starting the short walk to her home in Portswood, Southampton.
Hannah never made it and was found strangled two days later. Maninder Pal Singh Kohli, 40, denies her murder.
He also denies rape, kidnap and false imprisonment.
Oxford graduate and PhD student Miss Wilkinson told the court how the pair had been friends since they were 11 years old.
She said they both attended Barton Peveril College in Eastleigh near Southampton, where they were studying A-Levels, sharing the same subjects of chemistry and biology.
Miss Wilkinson told the jury that she and Hannah had met after college that day and decided to go out for the night in the Portswood area of Southampton.
The last picture of Hannah taken by a CCTV
She said they visited several bars, but only had one alcoholic drink all evening.
Miss Wilkinson told the court how they had arrived at a venue called the So bar by about 2230 GMT, where they talked about moving on to another bar.
Miss Wilkinson said: "We started to walk there and Hannah said: 'Shall we just not bother?' and I said yes, and we turned back.
"We started walking back into Portswood so I could get a bus home."
Miss Wilkinson told the jury how after she got on the bus, she waved at Hannah through the window as the teenager set off along Highfield Lane towards her home about 400yds (366m) away.
The jury of eight men and four women were told this was the last time that Hannah was seen alive.
In a statement, Hannah's mother Hilary, 51, gave an account of the hours before her daughter disappeared.
She said Miss Wilkinson arrived at the house and the pair went out for the evening at about 2000 BST.
In her statement, Mrs Foster said that when she woke the next morning: "I noticed Hannah's bedroom door was open and the landing lights were still on.
"If Hannah decided to stay overnight with a girlfriend, she would always let me know by text."
Mrs Foster said she had not received anything and, at 0630 BST, she phoned her daughter's mobile but there was no reply.
Maninder Pal Singh Kohli denies all the charges against him
Further attempts to contact Hannah were made before her father reported her missing to police at 1030 BST on the Saturday.
The jury also listened to a recording of the 999 call Hannah made as she was being abducted by her killer.
In it, her frightened voice could be heard as she made conversation with a man with an accent but the call was disconnected after 50 seconds because Hannah was not speaking directly to the operator.
Mr Kohli is alleged to have snatched Hannah from the street in his van in the moments after she waved goodbye to Miss Wilkinson.
Jurors heard on Tuesday that the teenager's blood was found in a van used by Mr Kohli, who took a flight to India two days after her body was discovered.
The trial continues.