History of violence: Abused women persuaded not to give evidence

More reports and background on Stephen Griffiths

He has been locked up twice before for violent crime, having stabbed a security guard and threatened a group of female students, and has been arrested six times for allegedly abusing ex-partners.

Despite this record, however, he did not feature on West Yorkshire Police's initial list of suspects for the Bradford killings – even though he lived less than a mile from where the victims went missing.

Detectives first suspected that the man responsible for the murders might have a history of using prostitutes, and Griffiths had never been arrested for kerb-crawling.

Griffiths was only 17 when he was first put behind bars in 1987, for wounding a security guard after being caught shoplifting.

He was given a three-year sentence for that attack, but was released in 1988 after the time he spent on remand was taken into account.

Griffiths's violent tendencies came to the fore again in May 1991 when he subjected four female students to a terrifying ordeal at Bradford College, where he was also studying.

He produced a knife from a carrier bag, went up to the girls and held it to the face of one of them, saying: "What are you laughing at, little girl?"

He then held the knife point to another girl's chin, before walking away.

Five days later, Griffiths pulled out a knife again after the father of one of the girls went to speak to him.

He was jailed for three years for the incidents in January 1992 after pleading guilty to two offences of affray and two of having offensive weapons.

He was then living in Oak Villas, the street in the Manningham area of Bradford where one of his murder victims, Susan Rushworth, was a resident before she disappeared last year.

Griffiths was treated at the high-security psychiatric Rampton Hospital, in Nottinghamshire, while on remand, but medics deemed him well enough to serve his sentence in prison.

Griffiths was arrested six times in 10 years for allegedly abusing ex-partners, but he was never prosecuted because the women refused to give evidence against him.

A police source said: "He is such a manipulative individual that he could get around these girls quite easily and convince them not to take it further."