The disappearance of Deirdre Jacob (19) last July near her home in Newbridge, Co Kildare, quickly raised suspicions in the minds of seasoned gardai that there may be a serial killer of women in the area. Ms Jacob's disappearance was a reminder of a similar event in virtually the same place almost two decades before when another young woman, Phyllis Murphy, was taken off a main road while making her way home in December 1979 and murdered.

Ms Murphy (23) was believed to have taken a lift from someone as she left her grandmother's house in Newbridge en route to her home in Kildare. A large-scale search of the Curragh and surrounding countryside was begun, but some gardai felt i that it was badly co-ordinated.

Four weeks after her disappearance, officers familiar with the Wicklow Mountains searched the Wicklow Gap above Hollywood and found Ms Murphy's naked body partially hidden among trees near Ballinagee Bridge. She had been raped and died from a form of strangulation known as vagal inhibition, where death is caused by cutting off the blood supply to the brain.

Detectives believed insufficient resources were dedicated early on, and by the time the body was discovered, the investigation was unlikely to succeed. A single man living near Kilcullen emerged as the main suspect, but there was insufficient evidence - or the genetic fingerprinting technology available - on which to base charges.

While Ms Jacob's disappearance is still officially a "missing person" investigation, gardai fear she has been abducted and murdered. The Garda Commissioner, Mr Pat Byrne, virtually conceded this on Thursday when he announced the establishment of a special detective unit to re-examine the cases of missing women believed to have been abducted and murdered.

There is good reason for a re-examination of such cases. In April 1995, during an examination of cases of missing women arising from the reinvestigation of the high-profile case of an American, Ms Annie McCarrick, who disappeared in June 1993, a remarkable oversight came to light. Detectives found that two of the women concerned had had a relationship with Michael Bambrick, a known sex offender from Dublin.

Bambrick was arrested and admitted the strangulation and rape of both Ms Mary Cummins (36), who had a 12-year-old daughter, in July 1992, and Ms Patricia McGauley (43), a mother of two, who disappeared in September 1991.

Bambrick admitted he had raped, strangled and dismembered both women and buried them on waste ground in Ronanstown, west Dublin. The remains were exhumed. Murder charges were dropped and Bambrick is serving a 10-year sentence for manslaughter.

The cases showed how little co-ordination there has been in Garda missing persons investigations.

There is no proper computer cross-referencing system and no proper central unit to deal with missing persons cases. With hundreds of missing persons reports annually (20 to 50 usually remain unaccounted for each year), it is inevitable that murders can remain undetected until bodies appear.

And bodies do, literally, reappear. On April 3rd, 1988, the decomposed body of Ms Antoinette Smith, a mother of two from Clondalkin, was found in a peat bog in the Dublin Mountains at Glendoo, Kilakee.

Ms Smith was last seen leaving Dublin city centre on the night of July 12th the previous year after coming from a David Bowie concert at Slane Castle earlier in the day. It is believed she, too, was raped, strangled and buried in a shallow grave. No suspect emerged in this case.

The suspicions about a serial killer taking women from the Dublin-Kildare-Wicklow area and burying their bodies in the Dublin and Wicklow Mountains have some foundation in fact. Since Phyllis Murphy's body was found in January 1980 up to eight women have disappeared and could have been abducted, murdered and some, at least, buried in the barren bogland and forest of the mountain range.

There is the still unsolved case of Ms Patricia Furlong, in her early 20s, who was found raped on July 24th, 1982, in a field at Glencullen. She had been at the Fraughan Beer Festival in Glencullen the previous evening. Gardai questioned everyone at the dance where Ms Furlong had been, including Vincent Connell.

Connell was rearrested in May 1990 and, on the basis of an alleged verbal admission to detectives, charged with murdering Ms Furlong. The trial jury accepted the statement but the case was later thrown out on appeal. Connell, who had a history of violence towards women, died of a heart attack, having always protested his innocence.

On June 23rd, 1992, yet another body appeared out of the bog only a mile or two from the site where Antoinette Smith was found. This time it was that of Mrs Patricia Doherty, in her 30s, who worked as a prison officer and had two young children. She disappeared two days before Christmas 1991 after leaving her home in Allentown, Tallaght, for last-minute Christmas shopping. She was found in a collapsed peat bank at Glassamucky Breakers, Kilakee, on June 23rd, 1992.

On March 3rd, 1993, an American literature student, Ms Annie McCarrick, who had come to Dublin some years earlier and fallen in love with the city and its adjoining hill country, left her flat in Sandymount for a trip to Glencullen and disappeared.

A major investigation was conducted. Ms McCarrick's family petitioned the US ambassador, Mrs Jean Kennedy Smith, which spurred the Government and gardai into the wider examination of missing women cases that led to the discoveries about Patricia McGauley and Mary Cummins - and to the door of Michael Bambrick.

However, there has been no sign of Ms McCarrick, who was described as trusting to the point of naivety. It is believed she, too, was abducted and killed and lies buried somewhere in the mountains.

Another unsolved disappearance which fits into the geographical and general picture of the suspected killer or killers is that of Josephine "Jo Jo" Dullard (20). Ms Dullard was last seen at 11.30 p.m. on November 9th, 1995, at a telephone kiosk, having left company in a public house in Callan, Co Kildare. It is believed she hitched a lift as far as Castledermot, never making it home to the village of Moone.

There has been no sign of her since. It is believed she, too, is buried in the mountains which loom to the east of the road from which she was taken.

Gardai suspect, but have no evidence, that Ms Eva Brennan (40), from south Dublin, who disappeared on July 23rd, 1993, was also murdered and buried. She disappeared after leaving her parents' home in Terenure to return to her flat in Rathgar.

The latest feared victim, the student teacher, Deirdre Jacob, was last seen walking home along Brennanstown Road, after having gone to Newbridge to post a money order to England on July 28th last.

Ms Jacob is described as a conscientious young woman. When her parents returned home at tea time the day she disappeared, they immediately feared for her safety and contacted gardai. The gardai quickly began to share the parents' fears and believe she, too, is the victim of an abduction and murder.

There are other unsolved disappearances and seemingly random murders outside this area. Ms Deirdre Mulcahy (19) was found raped and strangled on September 14th, 1989, in Midleton, Co Cork. A 25-year-old Cork man was subsequently charged and acquitted four years later. Ms Mulcahy's murder remains unsolved.

Ms Marie Kilmartin (36) disappeared from Portlaoise on December 16th, 1993. Her body, too, was found in a remote bog at Pims Road, half-a-mile off the Mountmellick-Portarlington road, six months later. A concrete slab had been placed on her chest, submerging her in the bog hole.

Ms Fiona Pender (25), from Tullamore, was seven months' pregnant when she disappeared on the evening of August 23rd, 1996. She was last seen leaving the flat which she shared with her boyfriend in Church Street, Tullamore.

A Dundalk woman, Ms Ciara Breen (17), was last seen when she left home at Bachelor's Walk in the town on February 12th, 1997. She took no possessions and, at the time of her disappearance, was in the middle of protracted orthodontic work to replace her front teeth.

Ms Fiona Sinnott (19), of Lady's Island, near Rosslare, Wexford, is also believed to have been murdered and secretly buried. Ms Sinnott was last seen in early February leaving a pub in Broadway, Wexford. Gardai have drained lakes and trawled across farmland but have found no trace of her.