RIO DE JANEIRO -- Lino Oviedo, a candidate in Paraguay's presidential election and one of the country's most polarizing political figures, was killed in a helicopter crash on Saturday night while returning from a rally in northern Paraguay, government officials said Sunday.
The death of Mr. Oviedo, 69, opens new uncertainty in Paraguay, where President Fernando Lugo was ousted under tumultuous circumstances last year. After the authorities confirmed Mr. Oviedo's death and called it an accident, officials in Mr. Oviedo's party, the National Union of Ethical Citizens, immediately questioned whether he had been assassinated.
Mr. Oviedo, a retired general who had led the Paraguayan Army, had a tumultuous political career. He initially gained prominence in 1989, when he helped topple Gen. Alfredo Stroessner, the dictator who ruled Paraguay for 35 years.
Mr. Oviedo fled the country in 1999 -- seeking exile first in Argentina and then in Brazil -- after being charged with organizing an aborted coup in 1996 against Juan Carlos Wasmosy, who was then Paraguay's president.
The authorities also indicted Mr. Oviedo on charges of masterminding the assassination of Vice President Luis María Argaña, who was killed by gunmen outside Asunción, the capital, in March 1999. But after Mr. Oviedo returned to Paraguay in 2004 and served time in prison in connection with the coup plot, Paraguay's Supreme Court absolved him of the various charges.
He then took up a hard-charging political career, campaigning as a populist who nimbly used Guaraní, Paraguay's widely-spoken indigenous language, in his speeches. He became known as the "bonsai horseman," in a nod to his short stature, and came in third in the country's last presidential vote, in 2008.
Paraguay was officially commemorating Mr. Stroessner's overthrow on Sunday, and some of Mr. Oviedo's supporters questioned the timing of the helicopter crash, which also killed an aide and the pilot. The Paraguayan aviation authorities said the helicopter went down during a storm in northern Paraguay and said they would investigate the cause of the crash.
"Twenty-four years ago today General Oviedo overthrew the dictatorship," César Durand, a spokesman for Mr. Oviedo's party, told Radio Ñanduti. "This is a message from the mafia," he said, employing a blanket term often used by Paraguayans to refer to shadowy organizations involved in drug trafficking and the smuggling of pirated goods into neighboring Brazil.
Mr. Oviedo's chances of winning Paraguay's presidential election, scheduled in April, appeared to be slim, political analysts said. According to recent polls, support for Mr. Oviedo remained in the single digits, placing him far behind the front-runner, Horacio Cartes, a banking and tobacco magnate.
The election comes after a stretch of political turmoil in Paraguay in which the Senate hastily ousted Mr. Lugo from office in June. Mr. Lugo, a former Roman Catholic bishop, had ended six decades of one-party rule when he was elected, but he faced fierce opposition from lawmakers in his attempts to reduce Paraguay's landholding disparities.
If Mr. Cartes, 56, holds his lead, the presidency will return to the Colorado Party, which has long dominated Paraguay. Still, his campaign is facing questions over his business dealings. State Department diplomatic cables obtained by WikiLeaks revealed allegations that a bank under Mr. Cartes's control was involved in money-laundering in 2007.
Mr. Cartes has denied those accusations, calling them "laughable rubbish."
This article originally appeared in The New York Times.