Six Colombians arrested as the alleged assassins of a candidate in Ecuador's August presidential election were slain Friday inside a prison in Guayaquil, officials announced, without providing details on what happened.

The prison authority said only that six prisoners killed inside Litoral Penitentiary were the men "charged with the murder of former presidential candidate Fernando Villavicencio." It identified them as: Jhon Gregore R., Andrés Manuel M., Adey Fernando G., Camilo Andrés R., Sules Osmini C. and José Neyder L.

Earlier, the agency had reported that "an event occurred inside" the prison and six people were dead. Litoral is Ecuador's biggest prison and is considered one of its most dangerous, being the scene of several riots with deaths the past three years.

The killings came as the prosecutor's office was near the conclusion of the investigation stage into the killing of Villavicencio, who was gunned down Aug. 9 while leaving a political rally.

The 59-year-old politician and former journalist had not been considered among the front-runners, but the assassination in broad daylight less than two weeks before the vote was a shocking reminder of the surge in crime besetting Ecuador. He had reported being threatened by affiliates of Mexico's Sinaloa drug cartel, one of the many international organized crime groups operating in Ecuador.  Villavicencio was outspoken about the links between organized crime and government officials.

Florida International University political science professor Eduardo Gamarra told CBS News that his outspokenness may have led to his death. 

"And one of the most notorious and prescient things that he said, that he always said, is that it would cost him his life."

Ecuador has long been known as one of the most peaceful nations in South America. But it is now becoming more violent, dangerous and deadly, Gamarra, an expert on Latin America, said.  He said the country's transformation is similar to that of Colombia during the height of the Columbian drug wars in the 1980s and 1990s, when journalists, judges and even a presidential candidate, Luis Carlos Galan, were murdered. 

Violence in Ecuador, a historically calm country, has surged in the past year as drug traffickers have flocked to the South American nation, resulting in a concerning uptick in drug trafficking, violent killings and child recruitment by gangs.

Villavicencio's alleged hitmen were captured hours after the crime and ordered held in preventive detention. Six other people also have been arrested for suspected involvement.

Although authorities released no information on the killings Friday, local media said the deaths occurred in pavilion 7, which officials have said is dominated by the local gang Los Choneros, led by Adolfo Macías. In his election campaign, Villaviciencio directly denounced Macías as the author of threats against his life. 

President Guillermo Lasso, who is out of the country, wrote on the social media site X, formerly known as Twitter, that he would return to Ecuador to attend to the emergency.

"Neither complicity nor cover-up, the truth will be known here," he said.

Ecuador is holding a runoff presidential election on Oct. 15 pitting the two top finishers in the August vote - leftist Luisa González and former lawmaker Daniel Noboa, who is the son of a banana tycoon.

In:
• Prison
• Ecuador