IN 2008 Rio de Janeiro’s state government started setting up police stations known as “pacifying police units” (UPPs) in the city’s favelas oakley sunglasses, or shantytowns. Previously these informal settlements had been abandoned to drug gangs and militias—protection rackets run mainly by off-duty and retired police officers. The first UPPs were in smaller favelas. But late in 2010 Complexo do Alemão, a cluster of a dozen favelas that together are home to around 160,000 people, was brought under the rule of law by the police and armed forces together. The area is due to get UPPs in 2012. (The army is still present in force.)

With Complexo do Alemão pacified, that left Rocinha, with around 100,000 residents, as Rio’s biggest favela still under drug traffickers’ rule. But the police are preparing for a showdown there too. In recent days they have set up police checks at entrances to the favela, and on November 10th they started helicopter flyovers to plan their approach. Civil police and the elite squad known as BOPE for its Portuguese acronym have been gathering and are apparently planning to enter on November 13th. Schools in nearby neighbourhoods have been closed since November 10th.

The operation has already claimed an important scalp: Antônio Francisco “Nem” Bonfim Lopes, who since 2005 has been the head of the drug gang that runs Rocinha, known as Amigos dos Amigos (Friends of Friends). He was discovered in a black Toyota Corolla leaving the favela early on November 10th. When the car was stopped at a roadblock, one of the men inside told police he was the honorary consul of the Democratic Republic of Congo and refused to let them search the car, claiming diplomatic immunity. When this was disbelieved another, who said he was a lawyer, offered the police 1m reais ($570,000) to let them go. When the car was searched, Nem was found in the trunk. (Congo’s embassy in Brasília has denied having any consular staff in Rio.)

His capture makes it less likely that the police invasion will turn into a bloodbath. Most previous UPPs have been installed days or even weeks after an ultimatum to the drug dealers to leave, the main aim being to reclaim territory for the state foakleys, rather than to take the drug traffickers dead or alive—and risk killing bystanders in the process. Nem was reported to have taken the stage at a party on November 6th in Rocinha and promised to stay and fight. But the police need to establish control quickly, before he is replaced. It was his predecessor’s death that allowed him to take over the gang.