Mr. Rodríguez Torres, a confidant of former President Hugo Chávez, had been considered one of the earliest stalwarts of Mr. Chávez’s political movement. He joined Mr. Chávez in a failed coup attempt in 1992 and spent two years in jail.
He served in Mr. Chávez’s government as chief of the secret police, and under Mr. Maduro was the interior minister before being abruptly fired in 2014.
Recently, Mr. Rodríguez Torres emerged as one of the most vocal critics to break with Mr. Maduro’s leftist movement. A tipping point came during protests last year when hundreds of thousands of people took to the streets to demand that Mr. Maduro step down.
In an interview last year, Mr. Rodríguez Torres sided with the protesters.
“Protesting is a right,” Mr. Rodríguez Torres said. “Who is not angry in this country? Who doesn’t have to skip work now because they have to go searching for medicine? Who doesn’t skip work because the minimum wage doesn’t allow them to buy their most basic food?”
After Mr. Maduro used force to quell the protests and created a new body that sidelined the country’s Congress, Mr. Rodríguez Torres began appearing publicly with members of the opposition.
Opposition politicians came to his defense on Tuesday.
“Miguel Rodríguez Torres also has human rights, and as a Venezuelan they’re important to me, too,” wrote Ramón Guillermo Aveledo, the former secretary general of the coalition of opposition parties.
As Mr. Maduro consolidated power, few were as willing to go as far as Mr. Rodríguez Torres in their criticism. One exception was Luisa Ortega, the country’s ousted attorney general, who tried to stop Mr. Maduro from using military courts to prosecute protesters. But Ms. Ortega fled the country shortly before the government charged her and her husband with criminal offenses.
By contrast, Mr. Rodríguez Torres stayed, continuing his criticism from within Venezuela’s borders.
“The government needs a president who is the head of state, one who can govern, and we don’t have this here,” he said in the interview last year. “We have so many problems that we can’t assume coherent policies — we can’t end our crime, we can’t resolve our economic problems.”