Police in eastern Slovakia have detained several Italians as they search for the killer of journalist Jan Kuciak, who was investigating possible links between the mafia and his country's political elite when he and his girlfriend were shot dead.
Slovak police chief Tibor Gaspar said detectives raided houses in the towns of Michalovce and Trebisov early on Thursday and took away seven people for questioning, including at least some whom he described as the "Italian fingerprint" in Kuciak's last, unfinished article.
Slovak and Italian media reported that those detained included Antonino Vadala, a businessman based in Slovakia, whom Kuciak alleged has connections to feared Calabrian crime organisation the 'Ndrangheta.
Mr Gaspar identified one of those held as "Antonino V"; the other six first names he gave are also common in Italy and extremely rare in Slovakia.
Italian prosecutors said they had alerted their Slovak and international colleagues “some time ago” to the Calabrians who were detained, and had provided information about their alleged ’Ndrangheta links.
Nicola Gratteri, a prosecutor in Calabria, told Italian radio that "it is likely that the families of the Calabrian mafia are behind the murder" of Kuciak.
The bodies of Kuciak and his girlfriend, Martina Kusnirova, were found last Sunday at his home in a village east of Slovakia's capital, Bratislava.
Mr Gaspar said the murder was probably connected to Kuciak’s investigative work, and the government offered a €1 million reward to help find his killer.
Mr Gaspar and interior minister Robert Kalinak, who is a close ally of prime minister Robert Fico, are under pressure to deliver swift results in the investigation or step down for their perceived failure to fight crime and corruption.
Mr Kalinak insisted on Thursday that he was doing everything possible to find the culprits, and had sought assistance from Italian, Czech, EU, British and US law enforcement agencies.
On Wednesday, Mr Fico's adviser Maria Troskova and national security council secretary Viliam Jasan resigned after the publication of Kuciak's final article, which revealed their alleged links to Mr Vadala and another Italian businessman with possible 'Ndrangheta connections.
“Connecting our names with this horrible crime...totally crosses the line,” the pair said in a joint statement.
“We categorically refute any connection with this tragedy. However, since our names are abused in the political fight against prime minister Robert Fico, we decided to leave our posts in the government office until the investigation is over.”
On the same day, Mr Fico lost another close ally in long-serving culture minister Marek Madaric, who said he felt duty-bound to step down after a murder that has shocked Slovakia and threatens to engulf its government.
Mr Fico and his Smer party face growing strain inside their ruling alliance, with the Most-Hid junior coalition party meeting on Thursday to discuss the government’s handling of the crisis.
The European Commission said it had requested information from Slovakia on reports – also stemming from Kuciak's work – that a mafia-linked farm subsidy scam may be operating in the east of the country.