A MURDER investigation has been launched by police after a postmortem examination revealed that a woman whose snow-covered body was found in Failand on Christmas Day, was strangled.

Joanna Yeates, was found by dog walkers at 9am on a roadside verge near the entrance to a quarry in Longwood Lane about three miles from her Clifton home, eight days after going missing.

Crews from Avon Fire and Rescue Service used winches and ropes to remove the body from the scene without disrupting any evidence.

At a press conference in Bristol on Tuesday, Detective Chief Inspector Phil Jones of Avon and Somerset Police revealed the results of the post mortem examination as he declared that her death was now officially being treated as a murder investigation.

He said Joanna, who disappeared on Friday, December 17, had died as a result of compression of the neck and appealed for any information about her murder.

He also said police believed her clothed body had been at the spot where she was found for several days.

DCI Jones said: "Somebody out there does know what happened to Joanna. What we have to do next is to try and find out why she was killed and who was responsible."

The team hunting her killer consists of around 70 police officers and staff who are appealing for the public's help to catch her murderer.

Police had initially expected results from the postmortem examination on Monday, but the frozen condition of her body meant pathologists cold not immediately examine it, leaving detectives and family members with an agonising wait to find out her cause of death.

Miss Yeates, an architect, was last seen alive on December 16, when CCTV footage showed her in a Tesco store on her way home to her flat in Canynge Road.

Her body was formally identified by her parents David, 63, and Theresa, 58, who on Monday made an emotional visit from their home near Romsey, Hampshire, to the site where she was discovered.

The distraught pair, who were joined by a small clutch of family members that included their son Chris and their daughter's boyfriend Greg Reardon, 27, laid a bouquet of yellow roses with a picture of their daughter on her graduation at the scene.

Bob Cook is a district councillor for Long Ashton and Failand.

He said: "It is dreadful and has been very upsetting for the people of both communities in Failand and Long Ashton.

"We never expect this sort of thing to happen where we live. It is very sad and our hearts go out to her family and friends, it affects so many people."

Richard Woodhurst, who lives in nearby Providence Lane, drives along Longwood Lane every day to go to the gym at Redwood Lodge and passed the spot where Miss Yeates' body was found four or five times after her disappearance.

The 68-year-old retired travel agent said: "It is so close to us, and it is disturbing that it could happen on one's doorstep.

"I went down Longwood Lane at about 8.30am on Christmas Eve to go the gym, and it is very disturbing to think that I would have passed right by her.

"Coming back home from there the road slopes downwards, so you are concentrating on braking before you come to the road and not looking at the verges.

"I have been up and down the road four or five times since she disappeared. I am amazed that I missed her body, but it is not something you look for.

"I'm just really shocked by it. It always happens in somebody else's backyard, not your own."

Val and Gerry Thomas, also of Providence Lane, drove down Longwood Lane at 8.50am on Christmas Day, just 10 minutes before Miss Yeates' body was discovered.

Mrs Thomas said: "We saw a couple walking a dog but nothing else. By the time we came back after a church service at 12.45pm the road was closed by police.

"We drove around and were stopped on Clevedon Road while the police got their vans and equipment up the lane.

"They were stopping all traffic on both sides of the road. At first we thought there might have been a car crash as they're quite common around here. But when everyone got out of their cars we saw an officer being interviewed and couldn't believe what had happened.

"We just went cold – there are always people in the lane walking their dogs and mountain biking. It's not a particularly quiet place, and often people park their cars there to go to Ashton Court. Somebody, somewhere knows what happened, and it's just absolutely horrific. We feel such distress for the family – their Christmases will be ruined forever now."

Forensic investigators have been examining the site since the tragic discovery in an attempt to find clues about her suspicious death.

Detectives are also examining CCTV footage from Clifton suspension bridge in Bristol, which is on the main route from Miss Yeates's house to where she was found.

The last known sighting of Miss Yeates was on CCTV as she bought a pizza at a branch of Tesco Express in the Clifton area on the evening of December 17.

Miss Yeates, who worked at BDP with Mr Reardon, was making her way home from the Ram pub in Park Street at about 8pm after a night out with work colleagues.

On her way home she rang her best friend Rebecca Scott to arrange to meet on Christmas Eve.

Miss Yeates lived with her boyfriend, who reported her missing on Sunday night after returning home from a weekend away in Sheffield visiting family.

Officers released footage of Miss Yeates buying the pizza in Tesco, which has become a key part of the investigation.

There was no trace of the pizza, the wrapping or the box in her home – despite the fact that the receipt, the coat she was wearing, and her mobile phone and keys were inside.

Anyone who can help the investigation can call the Operation Braid incident room on 0845 456 7000 or Crimestoppers on 0800 555.