More than 50 police officers who patrolled the same area in São Paulo, Brazil, were arrested on Tuesday, accused by state prosecutors of taking bribes from the country’s largest drug gang to allow its members to sell narcotics, the authorities said.

The São Paulo state police’s internal investigations unit, working with state prosecutors who focus on combating the powerful First Capital Command drug gang, known as the P.C.C., gathered what prosecutors said in a statement was proof of collaboration between officers and the cartel.

The P.C.C. has rapidly grown in strength in recent years, investigators say, and now largely controls cocaine and gun shipments into Brazil, as well as the flow of drugs grown in neighboring countries and shipped to Africa and Europe through Brazilian ports.

By late afternoon, 53 members of the 22nd Battalion of the São Paulo state police were under arrest — nearly 10 percent of that battalion’s entire force, according to state prosecutors. Three people suspected of being P.C.C. members were also in custody.