VALLETTA, Malta — More than two years after a car bomb killed Malta’s best-known investigative journalist, prosecutors in the Mediterranean island nation on Saturday charged a wealthy Maltese businessman with complicity in her murder and other crimes.

The arraignment of the businessman, Yorgen Fenech, a member of one of Malta’s most prominent and richest families, capped a tumultuous week in which a long-stalled investigation into the murder of the journalist, Daphne Caruana Galizia, suddenly picked up pace, ensnaring senior members of the government and Malta’s business elite.

Mr. Fenech, 38, who is suspected of paying three contract killers to carry out the murder, pleaded not guilty. He was arrested on Nov. 19 while trying to flee Malta aboard his yacht. Maltese military personnel halted the vessel as it set out to sea from a marina built by Mr. Fenech’s family conglomerate, Tumus Group, and forced it to return to port.

The killing in October 2017 caused outrage across Europe, putting a harsh spotlight on Malta, the smallest member of the European Union and a country denounced as a “mafia state” by Matthew Caruana Galizia, the journalist’s oldest son.