LOS TEQUES, Venezuela — When Judge María Lourdes Afiuni issued a ruling in December that irked President Hugo Chávez, he did little to contain his outrage. The president, contending on national television that she would have been put before a firing squad in earlier times, sent his secret intelligence police to arrest her.

Then the agents took her to the overcrowded women’s prison in this city of slums near Caracas. They put her in a cell near more than 20 inmates whom Judge Afiuni had sentenced on charges like murder and drug smuggling.

“I’ve received threats from inmates telling me they will burn me alive because they see me as a symbol of the system that put them in prison,” said Judge Afiuni, 46, in her prison cell. “I’m in this hell because I had the temerity to do my job as a judge in a way that didn’t please Chávez.”

Since Judge Afiuni’s imprisonment, a dizzying sequence of other high-profile arrests has taken place, pointing to Mr. Chávez’s recent use of his security and intelligence apparatus to quash challenges to his grip on the country’s political institutions. The arrests come at a time of spreading public ire over an economy hobbled by electricity shortages and soaring inflation.