A £10,000 reward has been put up in the hunt for the killer who strangled Joanna Yeates.

The snow covered body of the 25-year-old landscape architect was found on Christmas Day dumped by a roadside in Bristol, eight days after she went missing.

This morning independent charity Crimestoppers announced a reward of £10,000 for information leading to an arrest.

Meanwhile detectives are investigating whether Miss Yeates, who grew up in Hampshire, was seen leaving her Bristol flat with two people on the night she disappeared.

Avon and Somerset Police confirmed they were talking to Miss Yeates' landlord, Chris Jefferies, 65, who reportedly saw her leaving the flat in Clifton, Bristol, with two people.

''We are talking to the landlord and it is a line of inquiry,'' a force spokesman said.

Police also released CCTV footage of Miss Yeates buying drink from an off-licence on the night she disappeared. In the short clip, the 25-year-old is seen entering Bargain Booze on Bristol's Regent Street.

Robin Paine, who was working in the off-licence the night Miss Yeates was last seen alive, said detectives told her she had bought a small bottle of cider from the shop.

She said: ''I don't remember serving her and it was the Friday night before Christmas, between 8pm and 9pm and it is very, very busy. It's awful really, and unimaginable that someone can just disappear like that. It's really upsetting and I feel very, very sorry for the family.''

In another development police removed the front door of Jo's Bristol flat and took it away for forensic examinations.

Detectives leading the murder investigation said they are pursuing a number of lines of inquiry and maintained they were keeping an "open mind" over whether the former pupil at Sherborne House School in Chandler's Ford and Embley Park School in Romsey, was held captive or killed in the lane where she was found.

Her father yesterday spoke of how he felt "relief" after being reunited with the graduate's body, which was found on a grass verge in Failand, North Somerset, by dog walkers.

David Yeates, 63, from Ampfield, near Romsey, also said his family was trying to "rationalise" what had happened and hoped his daughter's killer would be brought to justice.

He said: "I fear that whoever has done this will never hand themselves in but we live in hope that the police will catch who is responsible.

"We are sure the police know more about what happened than they are telling us, but at the moment we are not questioning them because we feel they are doing their best."

Mr Yeates said the news that his daughter had been murdered came as no surprise to him or wife Theresa, 56, because the family had been told to prepare for the worst.

The past week had been the worst of their lives, he added, speaking from his home, but said viewing her body had made things a little easier.

"It was a relief to see her again - we just said 'Welcome back'," he said.

Avon and Somerset Police yesterday revealed that Miss Yeates died as a result of "compression of the neck".

Detective Chief Inspector Insp Phil Jones, who is leading the murder investigation, said he believed her body had been dumped in Longwood Lane, Failand, several days earlier.

The officer said a number of lines of inquiry were being pursued, including the possibility there was a sexual motive behind her killing or that the graduate knew her killer.

He confirmed that Miss Yeates' boyfriend, Greg Reardon, who reported her missing on Sunday night after returning home from a weekend away in Sheffield visiting family, was being treated as a witness and not as a suspect.

The landscape architect had been missing for eight days when her clothed body was discovered by a couple walking their dogs close to the Bristol and Clifton Golf Club - about three miles from her home.

Miss Yeates was last seen alive on the evening of December 17 having bought a pizza in Tesco Express in Clifton, at about 8.45pm.

Minutes before she had brought two bottles of cider from off-licence Bargain Booze, located just metres away from the Tesco store.

Police believe she then walked the short distance home to the ground-floor flat she shared with her boyfriend because her keys, purse and bank cards were found there, together with a receipt from Tesco.

Earlier that night she had left the Ram pub in Park Street in Bristol city centre where she had been having a drink with work colleagues and walked to Waitrose on the Clifton Triangle, before heading to Clifton Village and the Tesco Express.

Forensic officers yesterday continued the meticulous search of the Failand area and police were also examining Miss Yeates' flat in Canynge Road for signs of a struggle.

"There are a number of other lines of inquiry that we are pursuing," Det Chief Insp Mr Jones said.

"One of these is inevitably going to be how Joanna got from her home in Clifton to Longwood Lane, which is about three miles away.

"This means that we will be looking at any possible routes that could have been taken to get to and from that location.

"This includes reviewing relevant CCTV footage from cameras on the Clifton Suspension Bridge, which is an obvious link between the locations.

"However, this is just one of a number of routes that could have been taken, and we need to make sure we cover every possibility."

Miss Yeates' parents, close relatives and partner Mr Reardon made a heartbreaking visit to where her body was found to lay flowers on Monday.

Mr Jones appealed for anyone with information about her murder to contact police.

"Somebody out there does know what happened to Joanna,'' he said.

"Somebody out there is holding that vital piece of information we need to help provide Joanna's family with the answers they need and want.

"We know some of her last movements on Friday December 17. We know where and when she was found. We now know how she died.

"What we have to do next is find out why she was killed and who was responsible."