RIO DE JANEIRO — One politician was elected to Brazil’s Congress while under investigation for murder after having an adversary killed with a chain saw. Another is wanted by Interpol after being found guilty of diverting more than $10 million from a public road project to offshore bank accounts.

And Brazil’s highest court, the Supreme Federal Tribunal, convicted another congressman of having poor female constituents, who could not afford more children, surgically sterilized in exchange for their votes.

Across the nation, protesters keep taking to the streets by the thousands, venting their anger at a broad range of politicians and problems, including high taxes and deplorable public services. But a special ire has been reserved for Congress and its penchant for sheltering dozens of generously paid legislators who have been charged — and sometimes even convicted — of crimes like money laundering, bribery, drug trafficking, kidnapping and murder.

“Congress is without a doubt the most despised institution in Brazil,” said Maurício Santoro, a political scientist. “A good deal of this hatred is related to the fact that Congress has a tradition of preventing its own members convicted of crimes from ever going to jail.”