The delegation of cross-party MEPs is due to arrive on Wednesday to probe the circumstances surrounding the murder of the Slovak journalist and his fiancée, who were both killed in their apartment.
Police in Slovakia have said the murder is believed to be connected to his work as an investigative journalist; at the time of his death, he was investigating the mafia.
Police last week released seven people detained in connection with the killing of the journalist and his fiancée.
A police statement said the seven suspects, ranging in age from 26 to 62, were released because no evidence had emerged during the 48 hours they can be legally detained.
Kuciak, 27, had reported for the news site Aktuality.sk on fraud cases, including stories such as tax frauds with connections to high profile businessmen and government officials. He had also investigated the Slovak connection in the Panama Papers.
Kuciak was working on a story revealing the influence of the Italian mafia in Slovakia and its alleged ties to people close to the Prime Minister, Robert Fico.
Inge Gräßle, Chair of Parliament's budgetary control committee, will be part of the delegation on behalf of the EPP group. The other members are yet to be confirmed.
Speaking ahead of the visit, her party colleague Burkhard Balz said, “Considering suspicions that his murder was linked to his investigative work, it gives us a stark indication that some people are willing to go to any extreme to protect their financial practices.”
He added, “We will certainly be asking the Slovak authorities questions on the matters Kuciak was investigating.”
Further comment came from Parliament President Antonio Tajani, who is himself a former journalist and who stressed that it is “unacceptable that journalists can be killed for doing their work”.
“We have to ensure freedom of press” and that “journalists are able to work freely”, Tajani said. “I rely on Slovak authorities to reveal the truth”.
Tajani, an EPP group member, said, “We will not stop raising our voices and continuing to keep a watchful eye so that those who are guilty are brought to justice.”
The Slovak’s murder came just a few months after the murder of the Maltese journalist, Daphne Caruana Galicia.
On Friday, thousands of protesters braved icy weather to stage vigils across Slovakia and abroad, including in London, Paris and Brussels.
In the Slovak capital Bratislava, among the 20,000 protesters, some carried photographs of Kuciak and his partner along with a banner reading, “An attack on journalists is an attack on all of us.”