John Taylor, 46, from Cockshott Drive in the Bramley area of the city, was given two life sentences at Leeds Crown Court after admitting the 16-year-old's kidnap and murder.

Mr Justice Astill said to Taylor: "You are a dangerous sexual sadist."

Taylor: Killed Leanne for "sexual gratification"

He said it was as cold and calculating an act as he could imagine, and the suffering Taylor had caused could not be measured.

Police later warned that Taylor - who did not have a criminal record - could have killed before, and urged anyone with information about him to come forward.

Taylor stared straight ahead as the judge spoke, but there were cheers and applause from the public gallery.

Numb

Leanne disappeared after a shopping trip in the centre of the city on 26 November 2000. Her body was found in woods several miles away, nine months later.

The judge said Taylor had strangled Leanne to satisfy his "perverted cravings".

You are a dangerous sexual sadist - your purpose in kidnapping this young girl was so that you could satisfy your perverted cravings

Mr Justice Astill

The court had heard how Taylor grabbed Leanne on an unlit path she frequently used near her home in Bramley, blindfolded her and led her to his house, where he murdered her.

Leanne's mother Sharon Hawkhead - who described Leanne as a happy, confident and streetwise girl - said afterwards the family was still in a "living hell".

"Although John Taylor has been locked up, our agony continues...we are pleased that he has been locked up so he can't do this to anyone else, but life should mean life."

Detective Superintendent Chris Gregg, who led the investigation, said officers were now looking at other major crimes Taylor may have committed in the past 20 years.

He said he was looking particularly at the 1992 killing of Bradford prostitute Yvonne Fitt, and three other murders of which he declined to give details.

Dog clue

Leanne's body was found in August 2001, by a man walking his dog at a beauty spot about 16 miles from her house.

A forensic investigation of hairs found on her body led police to Taylor - and their inquiries turned up other evidence.

Leanne's mother Sharon said she had no feelings for Taylor

They discovered Taylor had had sado-masochistic relationships with girlfriends, and he had once told a girlfriend he wanted to sleep with her 15-year-old daughter.

Robert Smith QC, prosecuting, said the state of Leanne's body when it was found meant it was not possible to establish for certain whether she had been sexually interfered with.

Body stored

But Mr Smith said Taylor's motive was clear: "The motive for killing her was for the purpose of sexual gratification."

Mr Smith said Taylor had stored Leanne's body at his home - possibly in a fridge or freezer - for between three weeks and nine months, before dumping it.

A poacher who sold pet food and accessories from his home, police said Taylor had shown frequent cruelty to animals throughout his life and had an "extremely dangerous" nature.

Taylor, who is divorced, has a son aged about 21 and a 19-year-old daughter.