A series of congressional investigations in recent weeks has uncovered widespread official corruption in Brazil, roiled political circles and raised real, if slim, hope that the probes will lead to jail time for the most prominent perpetrators.

The investigations, known here as CPIs, have centered on banks and the judiciary, and on organized crime. Thus far, the organized crime investigation has been the most successful, as the panel has unearthed a web of corruption and criminal acts--in many cases involving drug trafficking--that has spanned 11 states and included more than 60 government officials.

The congressional investigation of the judiciary also has brought to light a scheme in which construction companies received $169 million in illegal payments in connection with the building of a labor relations court in Sao Paulo.

That investigation has led to allegations against Sen. Luiz Estevao, whose companies are said to have received $34 million in illicit payments. Congress has recommended his indictment, which may come before Christmas, and he could become the first Brazilian senator to be expelled. Estevao has denied wrongdoing.

These investigations "have done more in the past three months than the executive branch has been able to do over the past 20 years," said David Fleischer, head of Brazil's chapter of Transparency International, a Berlin-based anti-corruption organization.

But Fleischer and other analysts said the real challenge is whether law enforcement authorities can successfully prosecute the most deeply involved officials. "They seem to be testing the rule that says that in Brazil, no politicians go to jail," said Jose Luciano Dias, a political consultant in the capital, Brasilia.

President Fernando Henrique Cardoso has deemed the investigations crucial to denting the country's long and stubborn tradition of impunity but has repeatedly reminded Brazilians that the investigations have not tainted the government's highest-ranking officials.

"These are people I've never heard of," Cardoso said in a recent interview, referring to the state and local officials accused of involvement in organized crime. "There are some networks, but it's very dispersed. The [accused state] deputies are marginal."

Cardoso also has responded to the investigation by creating an anti-crime and -corruption unit that will use Central Bank investigators as well as federal police, prosecutors and tax officials to further root out illegal activity among Brazil's public servants.

Congressional investigations aren't new in Brazil, and these are not the first ones to uncover serious and widespread wrongdoing among public officials.

In 1992, in fact, an investigation ultimately led to the impeachment of then-president Fernando Collor de Mello, after he allegedly took kickbacks. Several high-level administration officials and friends of Collor were accused of criminal wrongdoing, but only one major player served jail time (and for only a few months).

The following year an investigation found that members of a congressional budget committee had funneled hundreds of millions of dollars to construction companies in a complicated kickback scheme.

None of the accused congressmen went to prison.

Consequently many citizens view parliamentary probes as little more than political theater that wins public relations points for the investigators but achieves little of substance.

"They make a lot of noise, but seldom does anyone go to jail or anything get changed within the system," said Eduardo Tinoco, 32, a professor of periodontology at the State University of Rio de Janeiro. "These ministers and politicians have a lot of money, and they hire good lawyers and they don't get punished. It's been like this for many years."

What has made these latest investigations unusual is that they have laid bare the kind of corruption among their politicians that Brazilians had long suspected.

Public officials allegedly have participated in intricate networks of drug trafficking and arms running, money laundering and truck hijacking.

State assemblies also are conducting 38 investigations, most involving administrative corruption.

"It has really shown the full spectrum of who's involved," Fleischer said of the probe of organized crime by the national congress. "Most of us didn't know there was such a broad involvement of people. That's the first time that's been done."