A Slovak court on Sunday ordered four people jailed until their trial for the murder of investigative reporter Jan Kuciak and his fiancee, a state prosecutor said.
The February killings sparked nationwide protests that toppled the government of Robert Fico, who had run Slovakia for all but two of the past 12 years.
Three suspects were detained in a house raid on Thursday morning and charged with murder on Friday.
The fourth suspect, a woman detained separately on Friday, has been charged with participating in the murder, which may have included helping, planning, ordering or organizing the killing, Kuciak family's lawyer, Daniel Lipsic, told Reuters.
Authorities released no further details on the four suspects and it is not yet clear when the trial might take place.
Kuciak had, among other things, investigated fraud involving businessmen with Slovak political ties, and the suspected mafia links of Italians with businesses in Slovakia.
A prosecutor said the February murder was likely a contract killing related to Kuciak's work.
His final story, published posthumously, reported on an Italian living in Slovakia with past business links to two Slovaks who later worked in the office of then-Prime Minister Fico.
Both of the Slovaks resigned, but deny connections to the murder. Their Italian former business partner has also denied having connections with the mafia and the murder, but was detained on a European drug trafficking warrant in March and extradited to Italy in May.
Weeks of public protests in March eventually forced the departure of the long-serving Fico but his three-party coalition has remained in power under Prime Minister Peter Pellegrini, who comes from the Smer party, which Fico still heads.
With your current subscription plan you can comment on stories. However, before writing your first comment, please create a display name in the Profile section of your subscriber account page.