On YouTube, he followed the "Extreme Right" channel. And he often said in web forums that he hated the "Castro-Chavismo" that fueled the military conflict that began decades in his native Colombia before he was born.
Like his family, Sepulveda admired U.S. backed former president Alvaro Uribe. He despised President Juan Manuel Santos for engaging in talks in Cuba with the Revolutionary Armed Forces of Colombia (FARC).
"I can't trust a president who has doubt about attacking a terrorist," Sepulveda tweeted April 10th. And on another public tweet, he said, Colombian vice president German Vargas Lleras and Santos "used to compete to see who was the strongest" and "today they are kneeling down in front of the FARC."
A few weeks away from the May 25th presidential election, Sepulveda was trapped in a bunker subjected to interrogations. A friend, who described him in Spanish as "un man berraco paraloco," slang for gutsy and paranoid, told Local 10 News that it was common knowledge that Sepulveda was working against Santos' re-election.
Sepulveda, his brother Luis Carlos Sepulveda, his uncle Jorge Ardila, his wife, Colombian actress Lina Luna Rodriguez, and her mother actress Myriam de Lourdes were paid consultants for the campaign of presidential candidate Oscar Zuluaga -- Santos' powerful rival.
Rodriguez, 29, told friends she was safe in the United States. She had 12,000 followers on Twitter.
Sepulveda's work on security and on political campaigns through South and Central America afforded him a posh lifestyle in Colombia's capital. He left evidence with his dad to show that for years he had also worked with police and military to fight crime and diminish socialist guerrillas.
Authorities raided their office, 93B No. 17-25, in Bogota Monday and Tuesday. Prosecutors said they had seized data related to negotiations with the FARC that began in Havana, Cuba, November 2012. They accused the software developer of being the leader of a spying ring, who may have been selling information.
Zuluaga turned his back on them Wednesday. In a press release on his website, he said he was not aware of the alleged surveillance or of any illegal activity.
"If someone has committed a crime they must be punished," Zuluaga said in a press release.
A day before the raid, Rodriguez's former employer JJ Rendon resigned as Santos' chief campaign strategist amid reports that before his work for the president he had received $12 million from "Los Rastrojos" drug lords to mediate their surrender. He denied it on Twitter.
Authorities uncovered another alleged surveillance operation in Bogota on February. It was also linked to the negotiations in Havana. On the web, users of a forum in Spanish poked fun at the operation saying that there were "too many others watching" or spying on talks in Cuba and situation on Venezuela.
Rodriguez, 29, and the Sepulveda brothers were among many Colombian young professionals who have been helping the student activist dissent in Caracas since February.
Rodriguez often used the hash tags #SOSVenezuela and #ChavismoParaDummies. Known among the Venezuelan exile community in Miami's Doral as an effort to help the dissent against President Nicolas Marduro in Venezuela.
Sepulveda also told friends he had gotten used to juggling death threats, was obsessive with his work and had problems sleeping. His friend remembered him saying that in his field of work people had to "be willing to make sacrifices." Sepulveda often tweeted to taunt.
April 11: "I like the smell of death." Feb. 23: "Today we will eat in hell." May 21: "I close my left eye so I can aim better."
Before his Twitter account was closed there was a trail left on Storify.com. Criminal defense attorney Luis Bernardo Alzate was defending Sepulveda, who is being charged with malicious use of software and intercepting data.