About 400 Brazilian police officers on Tuesday carried out an operation targeting the biggest criminal organisation in Rio de Janeiro state, arresting 26 people, the authorities said.The criminal group, which specialised in weapons and drug trafficking in the region, took in up to 7 million reais ($2.25 million) per month.The operation, which was conducted in the metropolitan areas of Rio de Janeiro city, Niteroi and Bajada Fluminense, is a new phase in an investigation that authorities have been pursuing for the past eight months.According to police, in recent months they identified the leaders of the group and determined their activities in the organisation, and this made it possible to simultaneously carry out quite a number of arrests.