A Slovak website has published the unfinished investigative report on alleged government ties to the mafia written by slain journalist Jan Kuciak.

Kuciak and his girlfriend, Martina Kusnirova, were found dead Sunday in their home east of Bratislava. It was the first time a journalist’s death in Slovakia was linked to his or her work.

Kuciak’s story describes the alleged connection between a suspected member of the Italian ‘Ndrangheta organized crime family in Slovakia and two senior aides to Prime Minister Robert Fico.

The two aides — security council secretary Viliam Jasan and chief state adviser Maria Troskova — say they are shocked by the murders but deny any connection to the killings. They say they are stepping down from their posts until the investigation is complete.

Fico called the shootings an unprecedented attack on the freedom of the press and democracy in Slovakia. However, he warned newspapers against linking “innocent people” to a double slaying “without any evidence. Don’t do it.”

Slovak police chief Tibor Gaspar said Wednesday that Kuciak and Kusnirova were most likely killed because of Kuciak’s work as an investigative journalist. He said both were killed with the same weapon, which is missing.

The shootings have outraged Slovaks. More than a thousand people turned out for an opposition-sponsored protest, and student marches are planned across the country Friday.

State Department spokeswoman Heather Nauert said the U.S. is “shocked and saddened” by the murders, and calls for a “swift, determined investigation” to bring the killers to justice.