Thames Valley Police have launched a team of detectives intent on cracking unsolved murders which happened in Oxfordshire, writes Crime Reporter Jo Duckles.

This week the Oxford Mail is reviewing some of those cases and today focuses on Janet Brown:

The beaten body of nurse Janet Brown was discovered just after 8am on Tuesday, April 11, 1995. Her body had been gagged and handcuffed and she had been repeatedly struck about the head.

It is believed she was in bed when she was awoken by the sound of intruders breaking in, and had gone to find out what the noise was.

Mrs Brown's family made a last heartfelt appeal for information in 2005, but no-one came forward. Since then forensic scientists have re-examined exhibits in the light of new technology, hoping to find the DNA profile of the killer, but to no avail.

Now detectives are appealing again for anyone with information to come forward.

Det Supt Steve Tolmie, of the major crime team, said: "I am waiting for the final reports from forensic scientists, but sadly this is still one of those cases that is unresolved.

"What we had to try and do was find a DNA profile alien to Janet Brown and her family.

"Once you find a profile, you need to identify that profile as belonging to an individual.

"All the testing we have done so far has been negative and the case will be reviewed again in two years' time.

"Despite extensive consultation, we are unable to resolve this particular case.

"We would like very much to be able to explain to the family what happened, but we are unable to. If there is anyone out there with information, please don't hesitate to contact us."

Mrs Brown was found naked and handcuffed, although there was nothing to suggest the attack was sexual. Her dressing gown was in the bedroom of her home at Hall Farm, Sprigs Holly Lane, Radnage, near Chinnor.

The house was not ransacked and as far as the family could tell, nothing was stolen.

A postmortem examination revealed she died from severe head injuries. A motive for the murder was thought to be burglary.

Her husband, Dr Graham Brown, was working in Switzerland and their eldest two children Zara, then 22, and Ben, then 21, had both left home. Roxanne, then 19, a student at Wycombe High School, still lived at home but was staying with a friend that night.

A friend of Roxanne's had rung the house at 8.30pm on April 10 and was the last person to speak to Mrs Brown. Her body was found the next morning by builder Nick Marshall and his 15-year-old son Ben, who were due to do work on the 11-acre estate.

After Mrs Brown's murder, police spoke to more than 2,700 people during an investigation, including hundreds of residents during house-to-house inquiries.

The death was featured on the BBC's Crimewatch UK as well as several national newspapers. Detectives thought the killing could be linked to the shooting of Dr Michael Meenaghan at his home in Blackbird Leys in December 1994, but that link was never proved.

Both victims were working on medical research projects at Oxford University when they died. Mrs Brown, 51, was employed by the university's department of public health and primary care, examining the health of women who had undergone treatment for infertility.

Police attempted to trace the drivers of two cars, a brown Ford Escort and a small car like a Fiesta or Metro, seen in the area at the time Mrs Brown died.

Five years later, in April 2000, Mrs Brown's murder was featured in the Oxford Mail as police made another appeal for information.

In 2005, the 10th anniversary of Mrs Brown's death, her husband and children issued a statement.

They said: "It tortures us that after 10 years, we still don't know who did this or why. The biggest worry is that her brutal killer is still out there, free to do the same thing again."