The 12, working on a water pipeline for the Croatian company Hidroelektra, were all Christians, and believed killed by one of the armed groups seeking to establish an Islamic republic in Algeria. The motive may have been to seek revenge for the plight of Muslims in Bosnia.
They were the latest foreigners killed since the warning to leave the country by 30 November or face death. The targeting of foreigners represented a major shift in tactics by Islamic militants.
And who said that terrorism did not pay? The murder of four foreigners the previous week had already achieved what the killing of more than 1,700 Algerians by Islamist extremists in the past 22 months had failed to do. For the foreigners' deaths have hit at the most vulnerable area of government enterprise, the national economy. The murders have promoted an exodus of the foreign expertise on which the country relies for maintaining the ailing economy. If exports fall, Algeria's ability to service its huge national debt will become even harder.
Last week's victims included Malcolm Vincent (a British computer engineer working on a liquefied natural-gas plant), a Spaniard, a Russian and a Frenchman. The response from the international community was mixed. The United States and German governments announced they were cutting their embassy staffs and advising their citizens to leave. Yesterday Canada said it was withdrawing the families of embassy staff.
Britain has not cut its embassy staff, but advises against non-essential visits to Algeria.
The crisis began on the eve of elections in January 1992. A month before, then president Chadli Bendjedid had evolved a strategy to crush the old guard of the FLN, the National Liberation Front which, after leading the bloody struggle for independence from France, had ruled as a one-party government for 30 years. The experiment was a disaster. As the old guard saw their power and influence about to be eroded, they intervened, cancelling the elections which the FIS, the Islamic Salvation Front, was poised to win.
The authorities, having rejected the ballot, resorted to repression to stamp out opposition. They jailed the leaders of the FIS. They banned its activities. And they have responded to attacks with force.
In their turn, the Islamist militants have become increasingly violent. And since the summer, the violence has taken a turn for the worse. It has become more surreptitious, insidious. People are more afraid to go out on the street. The escalation in violence, and the change in its nature, has raised fears that the Islamists have acquired a licence to kill.
According to a recent report by Article 19, the international centre against censorship, radical Islamic groups are now targeting for assassination prominent public figures, journalists, writers and intellectuals known for their opposition to the activities of the Islamist movement.
In the past nine months at least 16 journalists and writers have been assassinated.
Although few believe that Algeria's Islamic militants receive outside support, many of them are veterans of the Afghan war or trained with the mujahedin in Peshawar.
The government strategy has clearly failed to suppress the violence. Repression has not worked. Nor can it work. More than 3 million voted for the FIS in the first round of elections two years ago: they cannot all be silenced.
The High State Council, the five-man presidency which has ruled Algeria since President Chadli was ousted in January 1992, has been calling for a national dialogue of trade unions, professional associations and the legal parties, but not with the FIS.
Yet dialogue is not the simple alternative. There are always those who do not agree to dialogue, among them hardliners in the army.
Over the past two years the Islamist opposition has splintered into different groups. So even if a dialogue were initiated, there would be no guarantee that those who agreed to talk to the authorities would be capable of reining in the men with guns.
As the country goes into a collective tailspin, pressure is mounting for the army to intervene. And, as the situation worsens, it risks spreading tension throughout Muslim communities in Europe.