(CNN) -- Brazilian authorities arrested dozens of police officers on Tuesday, accusing them of taking bribes from drug traffickers.
The 61 officers were paid to turn a blind eye to criminal activity in Brazil's Rio de Janeiro state, state public safety officials said. Investigators were still searching for two other officers suspected of involvement.
An investigation revealed that the officers had received payments of 2,500 reals (about $1,200) every time they patrolled certain communities, the state-run Agencia Brasil said, citing authorities.
Tuesday's arrests, dubbed "Operation Purification," come as authorities work to increase security in Rio de Janeiro and stamp out drug gangs before the 2014 World Cup and the Olympic Games two years later.
In October, police said they seized automatic weapons, guns and grenades and arrested dozens of people in a series of Rio de Janeiro slum raids. They announced they were going into the communities days in advance.
Police said they take that approach to avoid major violence, but critics have said it simply gives criminals a chance to escape.
In Tuesday's operation, authorities said they also arrested 11 drug-trafficking suspects.
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CNN's Paulo Nogueira and Gabriela Matute Urdaneta contributed to this report.