Brazilian police have arrested 52 fellow officers suspected of involvement in drug-trafficking in the city of Rio de Janeiro.
The officers, from a police district on Rio's outskirts, were detained at home or as they arrived for work.
They are accused of taking money from drugs gangs to warn crime bosses about impending raids.
Earlier this year, extra federal troops and police were sent to Rio to help tackle a wave of violence there.
The detained police officers face charges including drugs and arms trafficking, extortion and criminal conspiracy.
They allegedly received between $1,000 (£500) and $2,000 (£1,000) a week, to warn the traffickers about planned police operations in shanty towns.
"Unfortunately, we have policemen involved with crime," said Rio de Janeiro state security chief Jose Beltrame.
"This work is not over and will continue."
Arrest warrants have been issued for several other officers.
The arrests represent nearly 10% of the police force in the Duque de Caxias district which has some 612 officers, Brazilian media reported.
Several suspected traffickers were also arrested during an operation in three shanty towns in the district.
The operation follows a similar move last December when 75 officers were arrested in Rio after an investigation into drug-trafficking and organised crime.