THE grieving sister of murder victim Heather Barnett has made an emotional appeal for help in identifying her killer.

Denise Levoir has told of the trauma suffered by Heather's children and said: "There is a killer out there who is controlling himself in such a way that nobody has identified him yet. The assistance of the public may draw this investigation to a close."

The case, which has been compared to an Agatha Christie novel by senior detectives, has taken further twists this week with the release of more baffling information.

But members of Heather's family and of the police team investigating her brutal death are confident the murderer will be brought to justice.

Her mutilated body was discovered in the bathroom of her home in Capstone Road, Charminster, Bournemouth, nearly ten months ago. Her breasts had been removed and placed next to her body and strands of cut hair placed in her hands.

Heather's body was found by her shocked children, Terry, now 15, and 12-year-old Caitlin.

The youngsters ran into the street, screaming for help, after making the horrifying discovery when they returned home from school.

"This crime appears to have been directed at the children as well as Heather" said her sister.

""They are trying to be brave but this is something that is going to be with them forever. Even going into a bathroom was difficult initially - someone had to sit by the door so that Caitlin could go in."

Police believe the killer meticulously planned his crime. A knife and hammer are believed to have been used in the attack, both of which were taken to and from the scene by the killer.

The hair discovered in Heather's hands was not her own and could not have been ripped from the head of the murderer because it was cut and not attached to roots.

"The worst thing is knowing that someone planned this with such detail" said Mrs Levoir.

"We can't forget about it for long - it is going on and on. Friday was an awful day for all of us because it would have been Heather's 49th birthday."

One of the biggest breakthroughs in the investigation came this week when police identified a type of trainer believed to have been worn by the killer. A footprint in blood has been linked to Nike Terra-Part trainers, a style of which only 1,000 pairs were sold in the UK.

Police are desperate to hear from anyone who owns, once owned, or recognises the distinctive trainers. They would like to know if anyone has seen another person wearing that style of trainers.

They are keen to hear about any pairs of the shoes, even if members of the public still own them. They were on sale in the Bournemouth area at the time of Heather's death for around £40.

The Terra-Part range was produced in four colours, black, white, blue and red, and has a distinctive tread pattern on the base, known as a goat's foot pattern. The footprint was that of a trainer size nine, nine-and-a-half or 10.

"We are determined to track down the person responsible for Heather's violent murder," said Detective Superintendent Phil James of the Major Crime Investigation Team.

"It's probably one of the most traumatic murders that you could imagine for two children to come home from school and find their mother brutally murdered in her bathroom."

Anyone with any information is asked to contact Dorset Police in confidence on 01202 222500 or ring the free and anonymous Crimestoppers line on 0800 555 111. A £10,000 reward is offered by the Crimestoppers Trust.