BRATISLAVA (Reuters) - Police in Slovakia have detained an Italian businessman who had been a subject of the last report by a murdered journalist, taking him into custody over an unrelated drugs charge, the general prosecutor’s office said on Tuesday.

A journalist lights a candle in memory of murdered investigative journalist Jan Kuciak, in Trencin, Slovakia, February 26, 2018. REUTERS/Radovan Stoklasa

Authorities said his detention was part of an international action that resulted in the arrest of 17 people.

In a statement, the Slovak general prosecutor’s office said it had detained Antonino V. on a European warrant issued by a Venice court. “The court asked for Antonino V. to be extradited for prosecution for a drug-related offence,” it said.

A spokeswoman for the general prosecutor’s office confirmed the individual was Antonino Vadala, who had been a subject of reporting by Slovak investigative reporter Jan Kuciak before he was found shot dead at home with his fiancee in late February.

Venice chief prosecutor Bruno Cherchi said in a statement Vadala was under investigation for being part of a group dedicated to “international drugs trafficking and money laundering” that used apparently legal channels to import drugs from South America.

Kuciak’s murder has shaken Slovakia, prompting mass protests that are threatening to topple the government.

Police have interviewed more than 100 people as part of the investigation. Vadala was among seven detained on March 1 but later released. No one has been charged over the killings.

Kuciak had reported on fraud cases, often involving politically connected businessmen. His final article - unfinished but published posthumously - looked at Italian businessmen in Slovakia with suspected mafia links, including Vadala.

Kuciak also reported that Vadala had past business connections with two Slovaks who later worked in Prime Minister Robert Fico’s office. Both of the government workers have resigned but deny links to the murder.

In an interview with Slovak news website Korzar on March 6, Vadala denied links to the Italian mafia or Slovak politicians. He said Kuciak mistook him for someone else with the same name but was killed before Vadala could meet with him and explain.