Brazilian police have shut down a purported bitcoin investment scheme they allege stole 1.5 billion Brazilian reals ($359 million).

According to the Paraná state government, civil police in the state raided an unnamed organization in Sao Paulo, Curitiba and other regional cities last Thursday, claiming the group promised as many as 5,000 victims that they could produce sky-high returns on bitcoin investments.

Scammers targeted their network of victims through social media. After the victims sent funds, the suspects told them to wait as their investments grew three to four percent daily. But victims were not allowed to withdraw, the police alleged, and their money disappeared.

The four-month investigation culminated Thursday when police filed charges of fraud, money laundering, criminal association and forgery against the group. They arrested nine individuals in a SWAT operation that involved 50 officers, 20 vehicles and a helicopter.

Previously, Brazilian government officials have used bitcoin for illicit purposes too. In 2018, police busted a $22 million operation that siphoned funds from a prison budget and laundered them through the cryptocurrency.