The Italian mafia extended their tentacles into eastern Europe a long time ago. So anyone who was surprised by the death last month of the Slovak journalist Ján Kuciak was not paying attention.

Kuciak, the second journalist to be murdered in Europe in recent months, was found shot dead alongside his partner, Martina Kusnirova, at their home on 25 February. Like Daphne Caruana Galizia in Malta, Kuciak appears to have paid the price for his investigative reporting. At the time of his death, he had been working on a story on the influence of the Calabrian mafia, the ‘Ndrangheta, on business and politics in Slovakia.

Mafia organisations were the first western businesses to develop long-term relationships with communist regimes and used them to gain a foothold in the east. Although they could not buy property during communist rule, the mafia could rely on two other things: political corruption, to facilitate their illegal traffic, and a near monopoly of the black market in western goods illegally smuggled into eastern bloc countries.

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This is why, when the Berlin wall came down, Italian crime organisations were perfectly placed to help legitimate Italian companies expand their operations into eastern Europe. They became “business consultants” to these companies, operating like services agencies, helping them to navigate bureaucracy and expediting permits. In addition, crime bosses provided cheap labour and ensured no interference from the unions – a true paradise for business investors.

Kuciak was one of the few journalists trying to investigate the murky links between businesses in Slovakia and the ‘Ndrangheta. In a country where there is no crime of mafia association, the issue had been largely ignored by both law enforcement and politicians.

Calabrian businesses associated with the powerful Bova Marina clans arrived in Slovakia soon after the fall of the Berlin wall to take over swathes of the country’s agricultural businesses and use them as cover to claim EU farm subsidies, without the government intervening.

But the business of most interest to the Italian mafia in eastern Europe is arms. Of all the eastern European countries infiltrated by the mafia, the former Czechoslovakia had an asset that made it especially attractive: the VZ-58, an assault rifle that can fire 30 rounds without being reloaded, a variation on the Soviet-made AK-47, but less expensive. The extensive arsenal of the former Czech army became the Italian mafia’s most lucrative business opportunity.

The mafia knows that these days, the murder of a journalist will bring just a few days of indignation

Slovakia was not an isolated case: the mafia’s arms business extended across the whole of eastern Europe.

And while the flow of drugs from the east traditionally went through Slovak territory, low-cost tourism opened up Bratislava to a younger, affluent market. Unprepared for the influx of cash-paying tourists, the city’s hotels and restaurants, prostitution and gambling rings – as well as the drugs trade on the streets – were being run by organised crime cartels.

If the ‘Ndrangheta, as suspected, executed Kuciak, it would be a first for the Calabrian mafia. They have never been known to attack a journalist before. One theory is that the killing was ordered by Italian mafiosi, but that the hit men were Slavs. The manner of the execution was inconsistent with Italian mafia style: carried out in Kuciak and his partner’s apartment rather than in a public place, to draw as much attention as possible.

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In recent years the mafia has preferred to destroy journalists’ reputations rather than resort to murder. If this was a mafia execution, it suggests that whatever information Kuciak had uncovered was so big it warranted his being silenced, whatever the cost. A killing like this would carry a high price in terms of police crackdowns and media attention, both of which would make it harder for the mafia to do business. But they will have decided that the sacrifice was necessary to protect more important, perhaps longer-term, interests. The execution of Kuciak also sends a message to others: “none of you is invulnerable”.

Killing journalists could be considered a strategic error, because the silencing instantly confirms the thesis the journalist was working on. But this only matters when campaigners and the media manage to keep the spotlight on the issue – and unfortunately, this is hard to sustain. The mafia knows that these days, the murder of a journalist will bring just a few days of indignation and stories in the national news pages.

The murder of Kuciak, a courageous young reporter doing his job, caused an outpouring of shock and international coverage. But nothing was done to protect him when he was alive – and this is the real scandal. Journalists are isolated, exposed, dragged through the courts accused of defamation, or sued for libel, like Daphne Caruana Galizia. In Europe, as in Latin America, the only journalist offered unconditional support is a dead one.

• This article was amended on 8 March 2018 to correct the reloading capacity of the VZ-58 rifle.