FOR a government that has promised to reduce violent crime, there can have been little better news than the arrest of Miguel Ángel Treviño Morales on July 15th. The head of the Zetas, a drug, kidnapping and extortion gang so notorious many Mexicans only whisper its name in public, Mr Treviño is allegedly responsible for orchestrating some of the country’s most sickening acts of violence in recent years. They include many beheadings, and the massacre of 265 migrants in 2010-11.

Yet the government of Enrique Peña Nieto, Mexico’s president since last December, is keen to play down drug-related violence. It reacted to its first toppling of a suspected kingpin in a markedly different way from its predecessor. Mr Treviño was not paraded in front of the press. There was little drama: he was detained with two alleged accomplices by a navy helicopter at 3.45am just south of the United States border and not a shot was fired.

The juiciest detail was that he had $2m in cash on him—enough, possibly, to counter the $2m bounty on his head in Mexico. (In the United States, it is $5m). Curiously, a video showed him walking casually through a detention centre without handcuffs. An official said that this was to preserve due process—so he could not be later freed on a technicality. But it made the capture of probably the most feared man in Mexico seem, if anything, an anti-climax.

Make no mistake, this was a big victory. The Zetas have terrorised their way across Mexico since they started as a group of special forces deserters in the 1990s. Their tentacles stretch from Texas to Central America. They have controlled the underworld in Mexico’s busiest border crossing, Nuevo Laredo, through which 10,000 trucks pass each working day. With the navy’s killing of the Zetas’ longserving leader, Heriberto Lazcano, last October, and now the capture of his successor, the organisation may be disintegrating.

The arrest sends a welcome message of continuity, both to the United States and to domestic critics of Mr Peña’s security policy. It shows that though the government has sought to silence discussion of violence, it has not abandoned the fight against organised crime. Earlier this year, anti-drug agencies in the United States were dismayed to hear that Mr Peña’s government planned to control access to their Mexican counterparts, but since then relations seem to have improved. It was not confirmed whether American intelligence helped in Mr Treviño’s capture. But analysts in Mexico think there is a good chance he will be extradited north.

Barack Obama praised the arrest as a sign of seriousness in the new government’s attempts to curb drug trafficking. But it will not necessarily reduce the flow of drugs across the border. Other mobsters, such as those from Sinaloa in north-western Mexico and from the eastern Gulf coast, will probably try to muscle into the Zetas’ territory (which could increase inter-gang violence in cities like Nuevo Laredo).

It does, however, reinforce Mr Peña’s message that his policies are aimed at bringing down Mexico’s level of violence. The Interior Ministry says killings related to organised crime have fallen by 18% in the seven months since the new government took over, compared with the same months a year before. Security analysts writing in Nexos, a monthly magazine, have questioned the government’s claims that violent crime has fallen thanks to its new security strategy. Using overall murder figures up to April, Alejandro Hope, an official in the previous government, says the downward trend started long before Mr Peña took office. Eduardo Guerrero Gutiérrez, another consultant, says the map of violence has changed, with killings rising this year in large metropolitan areas such as Guadalajara and Mexico City.

So Mr Treviño’s arrest comes in the nick of time. It sends a signal that the authorities are cracking down on the most extreme sorts of brutality, even if they have so far failed to capture the most wanted drug baron, Sinaloa’s Joaquín “El Chapo” Guzmán. This was more a victory in the war on violence than in the war on drugs. But with murders still almost double their level of six years ago, a long road lies ahead.