Two brothers accused of the murder of a Maltese investigative journalist have dramatically changed their pleas to guilty on the first day of their trial.

Only hours earlier at the start of the trial in a Valletta courthouse, George Degiorgio, 59, and Alfred Degiorgio, 57, entered not guilty pleas.

They are charged with planting a car bomb that blew up Daphne Caruana Galizia’s vehicle as she drove near her home on October 16 2017.

The trial judge, Edwina Grima, retired to chambers after the change of plea. She was expected to sentence both defendants later on Friday.

Prosecutors alleged that the brothers were hired by a top Maltese businessman with government ties. That businessman has been charged and will be tried separately.

In the run-up to the trial, the Degiorgio brothers had denied the charges. A third suspect, Vincent Muscat, avoided a trial after earlier changing his plea to guilty. Muscat is serving a 15-year sentence.

At the start of the trial, Alfred Degiorgio pleaded not guilty while his brother declared that he had nothing to say which the court interpreted as a not guilty plea.

During the prosecution’s opening arguments, the state argued they had evidence involving mobile phones that would link the defendants to the bombing.

The brothers had unsuccessfully tried to negotiate a pardon in exchange for naming bigger alleged conspirators, including a former minister whose identity has not been revealed.

The bomb had been placed under the driver’s seat and the explosion was powerful enough to send the car’s wreckage flying over a wall and into a field.

A top Maltese investigative journalist, Ms Caruana Galizia, 53, had written extensively on her website, Running Commentary, about suspected corruption in political and business circles in the Mediterranean island nation, an attractive financial haven.

Among her targets were people in then-prime minister Joseph Muscat’s inner circle whom she accused of having offshore companies in tax havens disclosed in the Panama Papers leak. But she also targeted the opposition. When she was killed she was facing more than 40 libel suits.

The arrest of a top businessman with connections to senior government officials two years after the murder sparked a series of mass protests in the country, forcing Mr Muscat to resign.

Yorgen Fenech was indicted in 2019 for alleged complicity in the murder, by either ordering or instigating the commission of the crime, inciting another to commit the crime or by promising to give a reward after the fact. He was also indicted for conspiracy to commit murder. Fenech has entered not guilty pleas to all charges.

No date has been set for his trial.

A self-confessed middleman, taxi driver Melvin Theuma, was granted a presidential pardon in 2019 in exchange for testimony against Fenech and the other alleged plotters. Two men, Jamie Vella and Robert Agius, have been charged with supplying the bomb, but their trial has not yet begun.