GardaÍ have begun preparing plans for the release of the country's only suspected serial killer, Larry Murphy, and will assign teams of up to 16 detectives to monitor him around the clock.

The Sunday Tribune understands that detectives from the National Bureau of Criminal Investigation (NBCI) and the National Surveillance Unit (NSU) have already started preparing for the release of the 45-year-old this summer.

Murphy, who is coming to the end of a 15-year sentence for rape and kidnap, is regarded as being a significant threat to women and is a serious danger of reoffending.

He is the prime suspect in the disappearance and suspected murders of at least three women in Leinster in the 1990s – Annie McCarrick, Jo Jo Dullard and Deirdre Jacob.

Murphy was interrupted by two hunters as he attempted to suffocate a woman with a plastic bag in the Wicklow mountains in February 2000. She had been abducted and repeatedly raped. No other women have disappeared since he was detained and jailed.

Garda management will take no chances when he is finally freed and have decided to post between 24 and 32 undercover officers working in two surveillance teams to follow Murphy wherever he goes for an indefinite period.

It is anticipated that the teams of undercover gardaí will work 12-hour shifts monitoring Murphy to make sure that he does not have the opportunity to reoffend.

Gardaí have set a precedent in recent years of following sex offenders who are regarded as being a high risk of reoffending.

Earlier this year an undercover team intervened to arrest a serial rapist who had broken into a house in Dublin's north inner city and was attacking a woman. He had been freed from prison for just 14 hours when he reoffended.

It is understood that Larry Murphy will have to abide by the provisions of the 2001 Sex Offenders Act and must inform gardaí where he plans to reside within seven days of his release. He will then have to tell gardaí if he plans to move or leave the country.

Sources believe that Murphy intends to live in Co Carlow when he is finally freed.

The job of preparing for Murphy's release is being handled by the Domestic Violence and Sexual Assault Unit within the NBCI.

It is liaising with the NSU and Serious Crime Unit about the supply of the undercover officers and detectives. Gardaí from wherever Murphy decides to live will also be involved in the surveillance operation. A senior garda source said: "Money is tight but Larry Murphy poses such a danger to women that he will be followed wherever he goes for as long as it takes regardless of the cost. We could not in good conscience just let him go about his business because he is too dangerous. What happens if another female disappeared and he was responsible? There would be a national outrage and we would be blamed. We are taking a zero-tolerance approach to him and will do everything in our power to ensure that he doesn't reoffend."

Gardaí from the cold case unit and Operation Trace, which is investigating the cases of six women who vanished in Leinster between 1993 and 1998, invited two FBI agents to Dublin two years ago to scrutinise the files.

The FBI concluded that the modus operandi and profile of the unknown suspect fitted Larry Murphy in three of the cases.

He has been effectively ruled out of being involved in the cases of Ciara Breen, Fiona Pender and Fiona Sinnott but gardaí believe that he kidnapped and murdered the other three women.

Detectives have interviewed Murphy on three occasions about the missing women but he has refused to cooperate.