Twelve people suspected of discussing plans to attack the Rio Olympics, including a "biochemical attack" on a water reservoir, were indicted in Brazil Friday, a source close to the investigation told NBC News.
The men were arrested in a series of anti-terrorism raids in late July, a couple of weeks before the Olympic Games. The group pledged allegiance to an ISIS offshoot, authorities said.
Brazil's Justice Minister at the time called the poorly organized group "absolutely amateur" with "no preparation at all." The source said the plot was more serious than initially described.
The men allegedly discussed a plan to contaminate one of Rio de Janeiro's water reservoirs to attack the Games, according to court documents reviewed by NBC News.