By Paulo Whitaker
RECIFE Brazil (Reuters) - Tens of thousands of Brazilians gathered on Sunday in the northeastern city of Recife to bid farewell to presidential candidate Eduardo Campos, killed in a plane crash four days ago, as debate swirled about the impact of his death on the October election.
Locals waited hours in line to pay their respects in front of Campos' coffin and watch an open-air mass attended by a number of Brazilian officials, including President Dilma Rousseff and her predecessor, Luiz Inacio Lula da Silva. She was briefly booed on her arrival.
Campos, a former governor of the Pernambuco state, was mourned at the entrance of the gubernatorial palace in a ceremony with intense media coverage.
"We lost a leader, one of the best governors that Pernambuco ever had," said Luiza Silva, 58, who criticized the presence of Campos' political opponents at his funeral.
The death of Campos, who was running third in opinion polls, is expected to upend Brazil's presidential race as it catapulted his running mate, renowned environmentalist Marina Silva, to the head of the presidential ticket of the Brazilian Socialist Party.
"I have the sense of responsibility and commitment imposed by the loss of Campos," Silva told journalists as she landed in Recife on Saturday. A devout Christian, she said an act of "divine providence" spared her from being with Campos in the private jet that crashed last Wednesday.
While the PSB, as Campos' party is known, is scheduled to officially launch Silva's candidacy on Wednesday, a first opinion poll showing the new political scenario is expected to be released on Monday.
The outpouring of public sympathy for Campos may at least initially translate into a popularity boost for Silva, who won nearly 20 percent of the votes when she first ran for president in 2010.
Pollsters and political commentators forecast that Silva is likely to come ahead of or statistically tie in second place with Senator Aecio Neves, an opposition presidential candidate who is running on a market-friendly platform.
Brazil's first-round vote is scheduled for Oct. 5. Rousseff, the incumbent president, leads opinion polls.
Some analysts said that if Silva makes it to a second-round runoff on Oct. 26, she will probably be a tougher contender than Neves as she is more likely to appeal to younger voters who are disillusioned with Brazil's political establishment.
Silva also has a loyal following among evangelical voters, an increasingly influential demographic in Brazil.
(Reporting by Paulo Whitaker; Writing by Walter Brandimarte; Editing by Jan Paschal)