A vote to restructure Venezuela’s government to give far more power to its leftist president was marked by tension on Sunday, as a candidate for the political body that would rewrite the Constitution was reported to be killed and many Venezuelans stayed away from the polls.
Prosecutors said on Sunday that they were investigating the death of José Félix Pineda, a 39-year-old lawyer running for the constituent assembly, the group charged with overhauling the country’s governing laws. An armed group broke into his home in the city of Ciudad Bolívar and shot him dead there, they said.
While the motive for the killing had not been determined, the news added to anxiety in Venezuela, where the government has banned protests by the opposition and journalists from entering polling places to observe the vote.
“I said rain, thunder or lightning, the 30th of July was going to come,” President Nicolás Maduro said, referring to the election, in a recording from his vehicle after casting his ballot.
The vote, ordered by Mr. Maduro, has raised fears throughout Venezuela that it could jeopardize the country’s democracy, which has been weakened by successive actions by Mr. Maduro and his loyalists.
The constituent assembly, which will have the power to rewrite the country’s Constitution and reshuffle — or dismantle — any branch of government seen as disloyal, is expected to grant virtually unlimited authority to Venezuela’s leftists.
Voters on Sunday could not reject the assembly’s creation, although some polls have shown that large majorities oppose it. All they could do was choose the assembly’s delegates from a list of candidates who are stalwarts of Mr. Maduro’s political movement.
The list of delegates includes powerful members of the president’s political movement, including his wife, Cilia Flores, and Diosdado Cabello, a leader in the ruling Socialist Party who was part of a failed coup attempt in the 1990s.
“This is an existential threat to Venezuelan democracy,” David Smilde, an analyst at the Washington Office on Latin America, a human rights advocacy group, said last week.
The vote follows a series of power grabs by Mr. Maduro.
First, the Supreme Court was packed with the president’s loyalists, and several opposition lawmakers were blocked from taking their seats. Then, judges overturned laws that the president opposed, and elections for governors around the country were suddenly suspended.
Next, the Supreme Court ruled in favor of dissolving the legislature entirely, but that decision was rescinded after an enormous outcry in Venezuela and abroad.
Infuriated by Mr. Maduro’s government, the opposition has mobilized more than three months of street protests. It has crippled cities with general strikes, rallies and looting. More than 110 people have been killed, many in clashes between the state and armed protesters. Few know how protesters will respond to the newly elected constituent assembly or its actions.