Three of the dead men, including Moneybags, were unquestionably major, full-time professional drug dealers, buying and pushing drugs on a large scale. The most recent victim, who died on Tuesday night, may not have been quite in their league, though he was awaiting trial on a charge of importing cannabis worth pounds 250,000.
The fifth killing is less clear-cut, for the victim had only a glancing connection with drugs, though he was well-known to detectives investigating armed robberies.
Since the IRA and loyalist ceasefires of late 1994 there have been a handful of other murders: a postal worker killed during a robbery, for which the IRA apologised; some Catholics killed by drunken loyalists; a loyalist dying in a revenge killing at the hands of his former associates.
Each time news arrives that a man has been shot dead everyone holds their breath for a moment, then relaxes when it becomes clear that the incident represents no threat to the ceasefires. Once this has been established these killings fade fast from the public memory.
The fact of these three drug-related deaths within a month is, however, raising new questions about who is responsible, and whether this much- increased killing rate could lead to a slide back to full-scale violence. Although the IRA has not admitted any of the killings, most assume they are its work.
Although the police are undoubtedly pursuing the gunmen, both the RUC and government ministers have been markedly evasive in answering questions about who is doing the killings. Senior spokesmen have in effect been at pains not to accuse the IRA of responsibility: politically, the name of the game seems to be to attempt to make a distinction between political violence and vigilantism.
All this is posing fundamental questions about Northern Ireland as a society, for the chilling truth is that the attitude of many sections of opinion towards the drugs killings is one of public silence but private applause. Drug dealers are regarded as the lowest of the low, and few shed tears when they meet sudden premature deaths.
Such attitudes are not confined to Northern Ireland, as Michael Winner's vigilante films suggest, but there are particular reasons why Belfast does not mourn the passing of such men. For one thing, a quarter-century of terrorism has inevitably inured many to the idea of violent death.
There is another reason. Belfast may have suffered terribly from terrorism, but the troubles had the effect of ensuring that it remained the most drug-free city in these islands. People now want it to stay that way.
In the 1970s the fact that both republican and loyalist groups made it clear they would kill dealers kept the city, apart from the traditionally bohemian student districts, relatively free of drugs.
This hard-line attitude softened in the late 1980s, particularly on the loyalist side, with increasing quantities of dope and tablets gradually making their appearance. In the early 1990s the IRA maintained its puritanical anti-drugs stance but in other quarters things changed dramatically. Some minor republican groups and some major loyalist figures, seeing the profits to be made, switched from condemning the drugs trade to actively trafficking in it.
But even then there were unwritten rules and regulations. Dope and Ecstasy tablets became more widely available but heroin and the like have been strictly taboo. Dublin, 100 miles and a three-hour car journey away, had thousands of heroin addicts, but in Belfast the drug was practically unknown.
The IRA made its attitude clear with several large-scale operations: in 1992, in one night, it killed one drug dealer and kneecapped another 10. In 1994, a few months before its cessation of violence, scores of IRA members took part in attacks which killed one dealer and injured a further 16.
In the republican districts where drugs were taking hold, many people openly approved of this violence against what were termed "anti-social elements," while many more displayed ambivalence. The IRA was widely regarded as keeping the problem at bay, so that when it called its ceasefire many feared it would have the unwelcome side-effect of opening up Belfast to heroin and cocaine.
That was, after all, exactly what happened in South Africa in the wake of the political settlement there. Before the agreement, drug abuse was mainly confined to marijuana and pills, but since then parts of the country, including Soweto, have been flooded with cocaine as a Nigerian drug cartel set about creating a new market.
In Belfast the quantity of marijuana and Ecstasy tablets available rose steeply in the aftermath of the ceasefires. The RUC reinforced its drug squad, but there was widespread public concern about the possibility of a flood of drugs, including cocaine or heroin.
The shootings of the four dealers have sent a message both to local dealers and to those who might be tempted to come in from outside. After the killing of Moneybags some of his associates stood in the street outside the bar and angrily shouted: "What ceasefire? What about the ceasefire now?" The message is that the IRA cessation does not extend to the drugs trade.
The killings may well have the effect of stopping that trade from flourishing, and of keeping heroin out of Belfast. In themselves these are laudable ends: the problem is the means by which they are achieved. Assuming the killers are the IRA, their activities are allowing the organisation to project itself as the defender of the community.
But in doing so it is keeping the flame of violence lit, demonstrating the power of the gun and projecting the pernicious message that, while political terrorism may be over, carefully directed violence is a useful tool of social control. If that continues, it will dash the hopes of those who hoped that paramilitarism would slowly but surely wither away, to be replaced eventually by a society in which the gun had no role.
Paramilitary violence since the ceasefire
l Republicans and loyalists have carried out 245 beatings since the ceasefire compared with 190 attacks in the previous 14 months. Of these, loyalists carried out 119 and the republicans 71.
l Since the ceasefire, loyalists have carried out 86 beatings whereas the republicans have been responsible for 159 - more than double the number for the equivalent period prior to the ceasefire.
l The latest figures indicate that there have been 27 murders in Northern Ireland since the ceasefire compared with 126 murders in the 14 months before the ceasefire.