Brazilian police detained 16 suspects who attempted to break into a branch of Banco do Brasil through a 500-meter underground tunnel connecting a bank to their rented property in Sao Paulo on this Monday.
Investigators believe the suspects had a plot to break into the government-owned bank through the tunnel, which is equipped with electric lighting and a ventilation system.
Chief investigator Fabio Pinheiro Lopes told The Guardian that this would have been the biggest bank robbery in the world because, if they had successfully tunneled in to the Central Bank branch, they could have stolen 165 million Brazilian reais (318 million US dollars).
The 16 suspects spent four months building the tunnel, which is made of wood and iron, investing a total of 4 million reais (over 1.2 million US dollars) in the plot.
But they were under police surveillance for more than two months and the authorities also found seven stolen cars at their hideout, which were intended to transport the stolen money.