FOR the criminal intent on murder a handgun - usually a 9mm pistol - is the favoured weapon.

In all the recent killings in Dublin, the killer has moved quite close to his victim. A handgun is easily concealed until the last moment, and offers the most flexibility and accuracy at close range.

More than 200 varieties of handgun have been made, many being imitations of the popular 9mm models made by large manufacturers such as Beretta and Browning. Unlike revolves, which need reloading after six rounds, automatic pistols usually have a magazine of between eight and 12 rounds.

Sawn off shotguns are more likely to be used for armed robberies. They are easier to obtain and very obvious when produced. Raiders find them effective for frightening large groups of bank customers and staff.

Many are relatively old and have been stolen from legal users of the almost 200,000 legally held guns in the State, 82 per cent are shotguns (the rest are rifles). All handguns are illegal in the Republic, except those issued to Army and Garda personnel.

In crime fiction, any fragment of a bullet is enough to lead a detective directly to a killer. In practice, ballistics experts are bused more to point out the likelihood of particular shootings being linked, so that surveillance can be placed on particular suspects.

Illegal firearms are available to rent in Dublin at a cost of up to £100.

The user will be obliged to dispose of the weapon if it has been fired and pay up to £300 in compensation to the owner.

The growth of the illegal drugs trade has coincided with an increase in the number of illegal handguns imported into the State.

Although ordinary crimes occasionally feature submachine guns, these more powerful weapons have generally remained in the paramilitary arsenals and have not been available to other criminals.