JUSTICE / SOUTH AMERICA : Vigilantes vs. the Rule of Law : In Argentina, crime is rising and the legal system is deteriorating. But should victims take the law into their own hands?

Horacio Santos, a 42-year-old nuclear engineer, had already been robbed 13 or 14 times, his family and friends say. When it happened yet again, he cracked--and a national uproar ensued.

At about 11 a.m. on June 16, Santos heard his car alarm go off while he was shopping near his home. He ran into the street to find two men stealing his car stereo. As they fled in an old Chevrolet, Santos leaped into his Renault Fuego and gave chase.

A few blocks away, he overtook and halted the thieves. In a rage, he fired two shots, one into each man’s head, killing them instantly.

In the days since the killings in the southern Buenos Aires suburb of Via del Parque, Argentines have been convulsed in arguments over their deteriorating justice system and whether an otherwise good citizen was justified in shooting two men dead for stealing his tape deck.

People talk of worsening crime, of inefficient and corrupt police--and some say, “Santos, well done.” Others cite the nation’s struggle to restore democracy after a brutal seven-year military dictatorship and worry that such vigilante justice threatens their hard-won rule of law.

Many cite the parallels to the case of Bernard Goetz, who shot at youths who surrounded him on a New York subway train in December, 1984. Goetz was later sentenced to one year in prison and a $5,000 fine.

But others point to differences in the two cases: Goetz appeared to be physically threatened; Santos pursued the thieves, who were apparently unarmed, caught them and shot them. The Goetz case had racial overtones, involving a white man and black youths. The Santos case is more a matter of class in racially homogeneous Argentina. He is solidly middle class; the slain thieves were poor, said to be suffering from the ravages of hyperinflation and recession.

Santos is in custody undergoing psychiatric testing. His lawyers say they will contend that he went insane momentarily from the combined effect of numerous previous robberies.

His car stereo had been stolen repeatedly--an epidemic in Argentina--and his wife and neighbors have been quoted as saying he had suffered 13 or 14 robberies in all. He had become a security fanatic, organizing a community watch and a private police post, increasingly common in Buenos Aires suburbs, and he was licensed to carry the .32-caliber revolver he used to kill the robbers.

The two victims, Osvaldo Aguirre, 29, and Carlos Gonzalez, 31, both were married with children and reportedly had criminal records on charges including robbery and drug possession. Their families’ lawyers are demanding at least eight years in prison for Santos.

Official figures show common crime has risen steadily in Argentina in recent years as the economy has worsened, although there is general agreement that Buenos Aires, a city of more than 10 million, remains far safer than most American cities. Nationwide, 659,869 crimes were reported in 1989, up 173,000 from 1987.

Bernardo Neustadt, Argentina’s most prominent talk-show host and commentator, wrote of the Santos case: “In the two certain bullets there is a notice to the thieves: The citizens are beginning to defend themselves. Take fright, you violators of the law. . . . I would have done the same, God forgive me.”

Neustadt’s comments drew warnings from officials and rival commentators that, however imperfect, the justice system remains the only alternative to the law of the jungle.