The plane crashed into three homes in Santos, on the coast of Sao Paulo, around 10 a.m., as it was attempting to land in bad weather. The Brazilian Socialist Party, of which Campos was the leader, tweeted it was "shocked by Mr. Campos' death."
Todos estamos chocados com a morte de Eduardo Campos, em queda de avião hoje de manhã. Marina Silva segue agora para Santos (SP).— RedeSustentabilidade (@maisumnarede) August 13, 2014
All seven people aboard the plane were killed, and six people on the ground were injured.
Brazilian authorities said the Cessna 560Xl took off from the domestic airport in Rio de Janeiro, headed to Guaruja, near Santos. Air Force officials said they lost contact with the plane after it was unable to land at Guaruja due to bad weather.
Campos was running third in polls for October's election, behind President Dilma Rousseff, running for reelection, and Aecia Neves, of the Brazilian Social Democracy Party.
Contrary to earlier reports, Campos' wife and youngest son were not on the plane. Neither was Campos' running partner, Maria Silva, who placed third in the 2010 presidential election and could take over as the party's candidate.
Rouseff canceled political engagements in the wake of the news and suspended her campaign, announcing plans to travel to Recife along with former president Lula da Silva for the funeral.
Brazilian president candidate Eduardo Campos died in Santos, São Paulo after his airplane crashed on a building. pic.twitter.com/PkDBSahACt— View of an Engineer (@jrprandina) August 13, 2014