Police thwarted a bomb attack that was planned for Lady Gaga’s historic concert that drew a crowd of more than two million people to Copacabana Beach in Rio de Janeiro on Saturday.

Local police shared how the plot was orchestrated by a group that promoted hate speech and the radicalization of teens, including self-harm and violent material.

As per the official data, 2.1 million people attended the American pop icon’s free show. The suspects were seen hiring participants, including minors, to conduct those attacks using improvised explosives and Molotov cocktails.

The Justice Ministry explained how the recruiters identified themselves as members of the global fan base, Little Monsters. The operation was based on a report by the ministry’s Cyber Operations Lab after a tip-off from Rio state police intelligence.

A man shared how the group’s leader was arrested in the southern state of Rio Grande do Sul for illegal possession of a firearm while a teen in Rio de Janeiro was detained for storing child porn.

Authorities carried out a dozen search and seizure warrants of 15 suspects across the states of Rio de Janeiro, Rio Grande do Sul, and São Paulo.