They are suspected of killing all kinds of people who happened to cross their path: the administrative director of a newspaper, a van driver who refused to pay a toll, two men who deliver gas cylinders, many random witnesses of their crimes, a man who complained that militiamen were recklessly shooting in the air, several homosexuals, the president of a samba school, a member of their own group who did a live transmission of a favela invasion, teenagers caught smoking marijuana, and even a bird thief. They have tortured two newspaper reporters and their driver. They also kill within their ranks when necessary: In the last 10 years, 25 of the 226 members of militia groups who were criminally indicted in the 2008 investigation that Ms. Franco worked on have been killed.

According to the civil police, the most powerful Rio militia, Liga da Justiça (Justice League), raises an average of 300 million reais, or about $80 million, a year through extortion and other unlawful activities. Today, militias are growing faster than other kinds of criminal organizations, also according to the head of Rio’s civil police. They usually exploit distinct black-market niches and concentrate on areas different from those of the drug gangs, so we could say that both ventures are complementary.

Drug gangs dominate favelas near the city center, the airport, the harbor and the main highways, from where it’s easier to control the distribution of arms and drugs. Militias are entrenched in more peripheral areas (like Baixada Fluminense) where they profit from the lack of basic services such as public transportation, water and gas distribution, internet and cable television.

That said, drug gangs and militias have different opponents as well. While the natural enemies of drug overlords are honest police officers and sensible legislators who can understand drug abuse as a public health issue, and thus support the legalization of drugs, a thorn in the side of militia leaders is a politician who calls for more government presence and better public services in the outskirts of town.

Either way, favela residents are tired of getting caught in the crossfire between heavily armed policemen, militia groups and drug gangs — many of them claiming to defend the community itself. The residents don’t need that kind of protection. They don’t need the presence of politicians who legislate for their own interests. They need to be seen as citizens who deserve basic rights, and not as business opportunities. Marielle Franco knew that.