GANG members from south west Dublin are still the principal suspects for the murder of the Co Wicklow publican, Thomas Nevin, last weekend and the raid on the north Co Dublin home of businessman James Fitzpatrick in the early hours of yesterday.

Mr Nevin's murder, during the late night robbery of his landmark public house, Jack White's near Brittas Bay, has highlighted the worsening spill over of crime into the countryside surrounding Dublin.

Crime in the Garda divisions surrounding Dublin is now understood to be rising faster than any other part of the country, prompting concern among gardai about the availability of policing resources in the area.

The ratio of crime per Garda in the divisions around Dublin is understood to be higher than the rest of the State.

The rise in crime in the region known as the "Dublin Rim - the broad semi circle of land around the city - is said by gardai to have several causes.

There is much easier access to the countryside around Dublin with the introduction of motorways and bypasses. There has also been a major population increase as dormitory suburbs have grown around provincial towns, particularly in Kildare, Meath and Louth, which is attracting criminals who carry out robberies on houses empty during working hours.

The worst crimes, where business people are held hostage at night and forced to hand over cash and jewellery, are believed to be the work of a small number of young criminals living in the west Dublin suburbs.

One particular group, known as the "M50 Gang", is a particular source of concern. This group has a core of about 20 members who have been in gangs together since their early teens. They are now aged between 19 and 24.

This group is blamed for the raid on the home of a Co Tipperary hotel proprietor last New Year in which the family was held prisoner and threatened with guns until they handed over a substantial amount of cash from the Christmas and New Year takings.

This raid bore similarities to the raid on Mr Nevin's public house on Monday morning. In the hotel incident, the robbers were described as being in their 20s, from Dublin and armed with at least one sawn off shotgun. They subjected the family to a prolonged ordeal before stealing cash from a safe and escaping. They also took the family's Opel Kadett car when they left.

The criminals who killed Mr Nevin drove to his home in a stolen car and also stole his car, an Opel Omega, when they left. His car was found later in south central Dublin.

Gardai suspect gang members from west Dublin, based in the Croftwood, Gallanstown and Ronanstown areas, were behind the Tipperary robbery and were also responsible for killing Mr Nevin.

Speculation that Mr Nevin was the subject of a professional assassination was not being taken seriously by senior gardai. The fact that large buckshot was used in the shotgun round which killed Mr Nevin was not regarded as significant. Number two and three buckshot, larger than the standard number four and five shot, is commonly used in Wicklow for shooting deer and other game.

The "M50 gang" invented its name as a result of its habit of driving across the M50 motorway into south Co Dublin where it steals fast cars to take on nocturnal raids into the countryside. The gang equips itself with radio receivers to scan Garda frequencies, walkie talkies and sawn off shotguns.

There is concern that the gang is building a criminal base in western Dublin and is moving into the drugs trade with the proceeds of its raids on rural business people. The gang's leaders are violent and are said to be mapping out careers as professional criminals.

The M50 Gang appears to be one of the largest and best organised of many groups involved in the raids across the Dublin Rim and further afield.

Last July, a Dublin criminal in his 50s drowned while trying to swim across the Shannon to escape gardai after a botched robbery in Limerick.

Among the raiders travelling out from Dublin is a small homosexual group of four or five men who steal powerful cars, hold up businesses and, it appears from examination of the recovered cars, have sex with each other in the cars on the way back to Dublin. The leader of this gang, a man in his mid 20s, has recently been released from prison after serving a sentence for robbery.

Several of the known robbers travelling out from Dublin, particularly those who randomly pick on abandoned houses in suburban areas, are heroin addicts. Some of these are HIV positive or have AIDS. Two HIV positive Dublin robbers recently caused considerable difficulties for gardai in Co Wicklow when they refused to leave their cell and threatened to bite officers. They were eventually overpowered and sacks placed over their heads.

The violence and recklessness of the Dublin raiders is said to have become a major source of concern for gardai in the divisions surrounding Dublin.

Senior gardai are particularly concerned that increased resources, promised by this and the previous government, have not materialised. In particular, a promised increase in civilian workers to free gardai for crime work, announced amid considerable publicity three years ago, has not taken place. In fact, the number of civilian jobs has declined as a result of Civil Service embargoes and this is said to have reduced the operational availability in the Force generally.

Figures supplied by the Department of Justice last week show Garda Siochana strength has declined since 1992 despite the public assurances about increasing Garda strength.

SINCE December 1992, the strength of the Force has dropped by about 200, from 10,959 to 10,751. Almost the entire drop has been in the garda rank. Mr Chris Finnegan, spokesman for the Garda Federation, said yesterday there was a depletion in the ranks of garda with retirements outstripping recruitment. He said there was "total demoralisation" among gardai about the lack of resources available to fight crime.

No significant numbers of extra personnel have been allocated to fight the rise in crime in the Dublin Rim.