The reporter discovered that Ms. Troskova had previously been a business partner of Mr. Vadala’s, according to the Organized Crime and Corruption Reporting Project. Mr. Kuciak’s published article did not suggest that she had any knowledge of or involvement with the ’Ndrangheta.
Ms. Troskova and Mr. Jasan, who headed the government’s crisis management office, resigned from their positions on Wednesday. They said in a statement that they were “shaken” by the killings, “just like the rest of Slovak public.”
“Connecting our names to this atrocious act by some politicians or media is absolutely unacceptable,” they added. “We categorically refuse any connection to this tragedy. But since our names are used in political fight against the prime minister Robert Fico, we decided to leave our posts at the government office until the end of this investigation.”
The culture minister, Marek Madaric, a member of the prime minister’s center-left party, also resigned, citing the murders.
“Of all the government, the Ministry of Culture is the most associated with the media,” Mr. Madaric said at a news conference. “As a minister of culture I can’t get over a journalist being murdered.”
“Information about a possible breach of any organized group among the politicians, to the level of state institutions, is serious,” he said. “It’s in the interest of us all, of the state, to investigate them as soon as possible — also to avoid making something into a case when it’s not.”
The bodies of Mr. Kuciak and his fiancée, Martina Kusnirova, both 27, were found on Sunday, three days after they were shot to death in what enforcement officials described as an intentional and expert attack. In announcing the killings on Monday, officials said it appeared that Mr. Kuciak had been targeted because of his work.
He was the second European journalist in recent months to be murdered while investigating possible corruption. In Malta in October, a car bomb killed Daphne Caruana Galizia, who had accused people close to the prime minister of corruption. Both she and Mr. Kuciak had worked on the Panama Papers, the trove of documents disclosed in 2016 by a consortium of journalists that showed how wealthy people around the world were hiding their riches.
The murders prompted a host of denunciations from European officials, including Mr. Fico, who said that violence and intimidation against journalists undermined civil society.
Mr. Fico announced a reward of one million euros for information leading to solving the crime. In an apparent reference to questions about Ms. Troskova, he told reporters, “Do not link innocent people, without any evidence, to a double homicide.”
Though not as well known as its Sicilian counterpart, the Mafia, the ’Ndrangheta “is among the richest and most powerful organized crime groups at a global level,” Europol, the European police agency, wrote in a 2013 report.
The group has invested its profits in legitimate businesses in many countries, and in places “has been able to achieve a position of quasi-monopoly in selected sectors, such as construction, real estate and transport,” the report said.