The country's police chief, Tibor Gaspar, told reporters in the eastern town of Michalovce on Thursday that about 10 people should be detained. Gaspar gave no details.
Slovak media report that one of the detained was Antonino Vadala, an Italian who did business with at least two officials close to Prime Minister Robert Fico. The officials resigned from their posts in the government office yesterday.
The bodies of 27-year-old Jan Kuciak and his girlfriend, Martina Kusnirova, were found Sunday evening in their house in Velka Maca, east of the capital, Bratislava.