ORGANISED crime may have been involved in the fatal shooting of an investigative journalist in Slovakia, a Canadian reporter has claimed.

Jan Kuciak, 27, is said to have been working on a story about possible Italian mafia involvement in fraud linked to EU subsidies in eastern Slovakia when he was killed.

The country’s newspapers dedicated their front pages to Kuciak, who was found dead alongside his girlfriend Martina Kusnirova at their house in the town of Velka Maca, east of the capital, Bratislava.

Kuciak is the first journalist to be killed in Slovakia. The government is offering a one million euro reward (£879,000) to anyone who helps authorities find the people responsible for the shootings on Sunday night.

In an interview with the Sme daily, Slovak-based Canadian journalist Tom Nicholson said Kuciak had told him shortly before his death that he was working on a story about possible Italian mafia activity in the east of the country.

Nicholson said he was ready to testify, but has not been approached by police yet.

The country’s police said the slayings were likely linked to Kuciak’s reporting, which also covered tax evasion, and which the journalist had said resulted in threats being made against him.

“I’m not sure what caused Jan’s death but I bet my life that this is so,” Nicholson said.

Aktuality.sk, the news website that Kuciak worked for, made the same claim as Nicholson in their own story based on the late reporter's work.

Sme also reported that two Italian businessmen with possible ties to the mafia operating in Slovakia did business with a senior adviser to Prime Minister Robert Fico, as well as officials from Fico's leftist Smer-Social Democracy party.

The opposition has called on national police force president Tibor Gaspar and Interior Minister Robert Kalinak to resign, and is planning a protest rally in Bratislava on Wednesday.

Fico dismissed the reports, saying: "You link innocent people to a double murder without any evidence. Don't do it."

The PM also criticised the opposition for using the case to smear his government.

Standing alongside Fico and Kalinak, Gaspar said investigators are taking media reports of possible mafia involvement as seriously "as any other version".

The police chief said investigators have been co-operating with the Czech and Italian authorities on the case as well as with Europol officials.

Analyst Milan Zitny said the killings place Slovakia in the company of undemocratic countries such as Ukraine or Russia where "the murders of journalists are nothing exceptional".

Government officials said: "We will spare no effort in investigating this criminal act and in bringing the perpetrators to justice."