(CNN) -- A hacker scandal involving a video is sending shockwaves through Colombia's presidential campaign just days before Sunday's election, making the already volatile electoral process even more contentious as parties accuse each other of dirty tricks and schemes.
The video published by the weekly news magazine "Semana" in Bogotá allegedly shows Óscar Iván Zuluaga, the leading presidential candidate, getting secret military information from a man who was arrested earlier this month and accused of illegal hacking activities.
Andrés Sepúlveda, 29, was arrested on May 5 and accused of "managing an illegal office dedicated to intercepting emails from between those close to the peace dialogues in Havana (Cuba)," according to a news release published by the Colombian attorney general's office.
The government of President Juan Manuel Santos, who is running for re-election, has held peace talks with the Marxist FARC guerrillas since late 2012.
Authorities confiscated 69 pieces of evidence, including computers and USB drives belonging to the suspect, according to the attorney general's office.
Zuluaga told reporters the five-minute video is "a vulgar montage" put together to smear his campaign.
"This video montage is a trap. It's no coincidence that it's been published when I'm on top in the polls and the president is going down," Zuluaga said.
Santos has not commented directly on the video.
A poll published by Ipsos Napoleon Franco on Friday, before the scandal broke, said Zuluaga would receive 29.5% of the vote versus 28.5% for Santos. Colombian law forbids the publication of polls seven days before a presidential election, so there's no way of knowing whether the scandal has changed last week's percentages.
Former President Alvaro Uribe, a Zuluaga supporter, called the video "a montage" and suggested the scandal is the creation of the Santos campaign.
"(Andrés Sepúlveda) is an alleged 'hacker' who has worked with (Venezuelan political strategist) J.J. Rendón, who's close to President Santos. In the video, they show Óscar Iván Zuluaga getting information that has already been in the rumor mill and has no relevance," Uribe said.
Rendón had been working for the Santos campaign but resigned earlier this month after accusations surfaced that he had received $12 million from drug traffickers in exchange for political favors in the Santos government. In the past, Rendón worked for Uribe.
Enrique Peñalosa, the Alianza Verde (Green Alliance) presidential candidate, told CNN affiliate Caracol TV he believes Zuluaga has committed a serious crime.
"We're talking about the crime of illegal wiretapping, conspiracy to commit a crime, and the crime of using military information and intelligence. We Colombians cannot resign ourselves to this. These are not the leaders we want," Peñalosa said.
Javier Restrepo, a pollster with Ipsos Napoleon Franco, says Colombian voters essentially face one choice: Do they vote for the candidate who wants peace talks with the FARC or the one who wants the guerrillas to surrender?
"The difference regarding the candidates' position in the economy and other issues is minimal, but when it comes to how to handle the guerrilla, it's abysmal," Restrepo said.
"Santos is advocating for a continuation of the peace talks he started in 2012, while Zuluaga's position is that there should not be a dialogue with an illegal guerrilla until its fighters surrender to government forces and lay down their weapons," Restrepo said.
There are five presidential candidates, but the only two with a real possibility of winning are Zuluaga and Santos, according to Restrepo. Colombian electoral law says to win a presidential election, a candidate must obtain 50% of the vote plus one vote, which means a second round on June 15 is very likely.