Daphne Caruana Galizia, a leading Maltese journalist who had reported extensively on government corruption, was killed in a auto bombing Monday, according to TVM, the country's public broadcaster.
Daphne Caruana Galizia, 53, had just driven away from her home in Mosta, a town outside Malta's capital Valletta, when the bomb exploded, sending the vehicle's wreckage spiraling over a wall and into a field.
"Everyone knows Ms Caruana Galizia was a harsh critic of mine, both politically and personally", he said.
"I will not rest until I see justice done in this case". "The only remedy for anyone who felt slandered was through the courts". Both Muscat and his wife denied the accusation and sued Caruana Galizia for defamation.
In June, Muscat was sworn in for a second term as prime minister following snap elections he had called to reinforce his government as the Panama Papers' leak indicated his wife owned an offshore company. Muscat easily won reelection.
Caruana Galizia was named by Politico as among the 28 Europeans who are "shaping, shaking and stirring" Europe. It gave no further information.
"The applicants have no trust in Magistrate Consuelo Scerri Herrera, and do not believe that she can conduct a magisterial inquiry through the seriousness and impartiality that is needed in the search for truth behind the brutal murder of journalist Daphne Caruana Galizia".
Adrian Delia, leader of the opposition Nationalist Party, described the event on Twitter as "the collapse of democracy and freedom of expression".
"We will not accept an investigation by the Commissioner of Police, the Army commander or the duty magistrate, all of whom were at the heart of criticism by Caruana Galizia", he said.
Muscat says her death resulted from a "barbaric attack" that also assaulted freedom of expression.
In another entry previous year, she wrote: "Malta´s public life is afflicted with dangerously unstable men with no principles or scruples".