The elections to a new legislative body faced violent protests in a country where one person a day has died in ongoing protests over the past four months.
The opposition leader had been sentenced to almost 14 years in prison in 2015 but was sent home amid massive protests.
Several months of protests in the country have left 90 people dead as the opposition demands a change of government.
The Instagram account for which Oscar Perez claims responsibility has more than 200,000 followers.
The dead protester was named as 17-year-old Fabian Urbina, who died from a gunshot wound in the chest.
The initiative aims to produce fact-based newscasts to reach people looking for alternatives to the country's mainstream media.
The team will face England at the U20 World Cup final on Sunday.
A vote on the controversial constitutional assembly is scheduled for late July.
Regional powerhouse Brazil slammed Maduro's move to appoint a constituent assembly as "a coup."
Anti-government protests demanding new elections in Venezuela have run into a second week.