Postscript : Did Embassy Bombers Commit Perfect Crime? : More than four months later, there are few clues as to who killed 29 people at the Israeli outpost in Argentina.

More than four months after a terrorist bomb destroyed the Israeli Embassy in Buenos Aires, killing 29 people and injuring more than 200, Argentine investigators have shown little progress in their efforts to break the case.

“I think this might be the perfect crime,” remarked an Argentine source who has followed the investigation closely. “They killed 29 people, and we probably will never find out who they (the bombers) are.”

Whether or not that proves true, it is now more frighteningly clear than ever how well planned and executed the March 17 bombing was--and how difficult it is for a country like Argentina, far from the bloody intrigues of the Middle East, to deal with this kind of crime. The success of the strike against Israel in a country where such a blow was unexpected, and where authorities were unprepared to trace the carefully covered tracks of international terrorists, may give incentive for similar actions in the future.

“These things are hard to investigate,” the source said. “There is no evidence.”

And just as there is no known sign of the terrorists, soon there will be no visible remains of the embassy. On a cold day last week, a wrecking crew was finishing the work of the bombers at the corner of Arroyo and Suipacha streets in downtown Buenos Aires. Workmen with pickaxes were breaking down the embassy’s few remaining walls, and a power shovel was scooping up debris in jumbled piles of brick, concrete and wood.

A man in a turquoise sweat shirt, balanced on top of the last jagged piece of an interior second-floor wall, attached a cable from a red crane, then climbed down. The crane moved, the cable went taut and the wall came tumbling town in a cloud of dust.

Meanwhile, the Israeli diplomatic mission is occupying temporary quarters on an upper floor of a modern high-rise building three blocks from the Pink House--Argentina’s presidential palace. Asked about progress in the investigation of the March bombing, an embassy spokesman said: “The investigation is being carried out by the government of Argentina.”

Experts from Israel’s Mossad intelligence service, the CIA and other foreign investigative bureaus came to Argentina after the bombing to help in the case, but they all reportedly have gone home without providing any crucial information.

Argentine federal police, border police, army intelligence agents and judicial investigators all have conducted parallel probes in the case and have maintained official silence on their work. But according to leaks in the press and other accounts, they have yet to identify a plausible suspect.

Investigators are said to agree that the bomb was a charge of plastic explosive carried in the bed of a Ford pickup that stopped on the sidewalk outside the embassy on Arroyo Street. A watchman from a nearby building has said the vehicle was a light-colored car, but that version has been discounted because scattered parts of the pickup were recovered. The fate of the driver is still unclear.

A statement issued in Beirut the day after the explosion claimed responsibility in the name of Islamic Jihad (holy war), a name favored by Shiite Muslim groups that have carried out previous terrorist attacks in the Middle East. The statement said the embassy bombing was a suicide attack by “Abu Yasser,” an Argentine who had converted to Islam.

No further evidence has come to light on the identity of the driver. A man using a presumably false Brazilian name, Elias Ribeiro da Luz, had purchased the Ford pickup from a used-vehicle agency, but investigators have not tracked him down.

Prof. Ariel Merari, an expert on terrorism at the University of Tel Aviv, visited Argentina after the bombing and told reporters that the pro-Iranian Islamic Jihad or the related Hezbollah (Party of God) organization probably organized the attack with local support and explosives bought in Argentina. U.S. and Argentine officials also have voiced suspicions that Hezbollah was behind the plot.

Merari said the international terrorists probably chose Argentina as the site after discarding countries where governments are less friendly toward Israel and its allies, or where security agencies are better prepared for such attacks. Other considerations may have included the fact that Argentina has a large Jewish community and that the Argentine government had broken an agreement to supply Iran with enriched uranium, Merari said.

The Argentine Supreme Court opened a judicial investigation after four Pakistani citizens were arrested in connection with the blast. The case is still open and judicial aides continue to question witnesses, but the four Pakistanis have been released on their own recognizance--a sign that they are no longer regarded as suspects.

One witness who was questioned recently said the investigators seemed to be probing in the dark. “They have absolutely no clue, this is my impression,” he said. “If things go on like this, the investigation is going to remain inconclusive.”

Some newspapers have offered a ray of hope for breaking the case, speculating that Monzer al Kassar, a Syrian-born arms merchant who was in Argentina around the time of the bombing, may have information on the plot.

Kassar, arrested in Spain last month, has been accused of supplying arms to terrorists but not of being a terrorist himself. He is wanted in Argentina for alleged fraud in obtaining Argentine citizenship, and he also has been linked to an Argentine drug-trafficking scandal.