Kevin Mallon is accused of illegally selling tickets at exorbitant prices.
He works for British ticketing firm, THG Sports, which was the Olympic Council of Ireland’s official ticket re-seller for the London 2012 games.
Mallon was arrested on Friday along with a translator.
They’re said to have been caught with dozens of tickets – some of which feature the name of the Irish Olympic Council.
The council has launched an investigation into how their tickets allegedly became involved.
Police in Brazil believe they have dismantled a major international touting ring and have confiscated more than 1,000 high-value Olympic tickets.