THE seedier side of Pierremont Crescent was beginning to show through by October 1996. The genteel Victorian villas were being broken up into flats rented by Darlington's growing student population - an island of bedsit-land among the 19th Century grandeur.

And in one of those basement bedsits unfolded perhaps the most vile crime ever perpetrated in the town.

On a cold October day, detectives discovered the naked and decomposing body of 29-year-old Lesley Fox, in her basement bedsit. She had lain dead for five days.

The young woman, who was four months pregnant, had been subjected to a prolonged and violent sexual assault before being strangled.

Her body, which was discovered on the bedroom floor, could only be identified by dental records.

And as a team of more than 50 officers worked round-the-clock, their investigations exposed a murky underbelly of sexual depravity and ritualistic murder.

At the time, the man leading the murder investigation, Detective Superintendent John Graham, described the circumstances of her death as "disturbing and bizarre".

The shocking crime scene which met those arriving at her flat was like nothing even hardened officers had seen before.

Miss Fox had been strangled with a rope, her naked body had been carried from the living room into the bedroom where the sexual assault had continued, and a duvet and vacuum cleaner were carefully arranged around the body.

Twelve days after the art graduate's body was found, Timothy Dunn, then 15, and Norman Bowen-Jones, who was 17, appeared before Darlington magistrates charged with her murder.

But it was only a year later when the case came to trial at Teesside Crown Court that the true extent of Mis Fox's torment came to light.

The court was told that the boys, lifelong friends who went on to have a gay relationship and led a tangled sex life, had fantasised about having sex with Miss Fox before murdering her.

The prosecution alleged that they went to her flat that night with the intention of turning their fantasy into reality.

Both denied murder - and while they both admitted being at her flat at the time of the killing, they blamed each other for her death.

Miss Fox, who was unemployed and lived alone, was described as a bright and vivacious woman who was vulnerable.

She had been receiving psychiatric treatment at Darlington Memorial Hospital for her schizophrenia.

Speaking at the time of the trial, her mother, Sylvia Fox, said: "Lesley was too good, and would believe and trust everybody. She was the kindest person you would ever meet."

Det Supt Graham, who has since retired from Durham Police, told how the pair had visited Miss Fox on several occasions, realised how vulnerable she was and exploited this to gain her trust up to the point where they killed her and degraded her body after her death.

Dunn told the court he had had a sexual relationship with his lifelong friend Bowen-Jones and that he loved him and wanted to spend the rest of his life with him. Bowen-Jones denied the suggestion.

The pair were convicted of murder on November 11, 1997.

As Mr Justice Douglas-Brown sentenced them, he said: "Although you were only 15 and 17 when you murdered this woman, you showed a cold detachment in what you have done.

"It leads me to think, along with the circumstances of the killing, that you are both very dangerous.

"It was a cold-blooded, senseless and barbarous act, and difficult for ordinary people to understand."

Dunn was ordered to be detained at her Majesty's pleasure. Bowen-Jones was sentenced to life in a young offenders' institution.