THE gruesome murder of a prostitute 15 years ago will be re-examined, detectives have pledged.

Officers in the Bolton-based Cold Case squad will reopen files on the killing of Maria Requena in January, 1991.

Her body was found by two young anglers after it had been hacked to pieces with power tools and stuffed inside five bin bags - one containing her severed head - at Pennington Flash, Leigh.

Detectives at the Cold Case Review Unit, which operates from Castle Street Police Station, hope that advanced DNA profiling, not available at the time of the murder, may help them trace the offenders.

Det Insp Jeff Arnold, who heads the unit, said: "It was a horrendous case and it demands to be looked at again.Because of what she did, she was very vulnerable, and often women in her position become targets for the most sadistic members of society."

Det Insp Arnold and a team of detectives are also investigating the death of prostitute Linda Donaldson, whose body was found less than three miles from Pennington Flash 14 months before the discovery of Maria's body. Police investigating the two murders in the 1990s said the same man might have been responsible for both.

But Insp Arnold said: "Forensically there is no link, and we will be looking at the two deaths in isolation until anything suggests we should do otherwise."

The Cold Case Review Unit has more than 70 other unsolved cases on its books - some up to 50 years old.

These include the unsolved murder of grandmother Shirley Leach, who was sexually assaulted, strangled and mutilated at Bury Bus Interchange in 1994.

Schoolgirl Lisa Hession was murdered in Leigh in December, 1984, and police began looking at new information last year following a Crimewatch appeal on the 20th anniversary of her death.

The team may also one day be asked to probe the murders of Bolton pensioners Phyllis Mayoh and Danny McFadden.

Mrs Mayoh, aged 88, died three days after confronting a burglar in her home in Daubhill in April, 2003. Mr McFadden, aged 65, was beaten and set on fire at his Halliwell home in 1998.

The Cold Case unit was set up in 2004 following the success of similar squads in America. It is also investigating more than 40 unsolved rapes.

Detectives in the unit had their first success last September, when porn baron Bryan Keen, of Wilmslow, Cheshire, was convicted of a rape he had committed 11 years previously.

In October, rapist Darren Nicholas Jennings, of Cheetham Hill, Manchester, became the second person to be jailed following work by the unit.