One of three men accused of killing Maltese investigative journalist Daphne Caruana Galizia in a car bombing has changed his plea to guilty and was sentenced to 15 years in prison.

Vince Muscat, together with brothers Alfred and George Degiorgio, had been accused of detonating the bomb that killed Ms Caruana Galizia as she was driving her car on October 16 2017.

Court proceedings against the Degiorgio brothers, who have maintained their not guilty pleas, will continue.

A fourth man, hotelier Yorgen Fenech, is being charged separately.

The scene of the bombing in 2017
The scene of the bombing in 2017 (Rene Rossignaud/AP)

Ms Caruana Galizia’s killing led to international calls for accountability, as her investigative reporting had targeted the government of then-premier Joseph Muscat with claims that corruption was everywhere in political and business circles in the tiny EU island nation.

Joseph Muscat, who is no relation to the suspect, resigned last year in the wake of the scandal.

Vince Muscat had initially pleaded not guilty, but during a court hearing on Tuesday to hear evidence in the case, his lawyer announced the change of plea.

The court warned him about the consequences of his admission, but he reaffirmed his guilty plea, which resulted in a shorter sentence.

He will start serving the term immediately.

As the dramatic development took place in the Valletta courtroom, police arrested three men believed to have supplied the device that killed Ms Caruana Galizia. They are set to be charged in court in the coming days.