A reserve juror who served in the trial of Yorgen Fenech was arrested on Friday morning and is expected to be questioned by police later in the day, Times of Malta reported.

The arrest comes a day after other jurors in the case were arrested and questioned by police over suspected breaches of the oath taken before the trial began. The husband of one of the jurors was also arrested on Thursday.

The jurors were reportedly questioned by officers from the Financial Crimes Investigation Department (FCID), which deals with financial and economic crimes.

Police said on Thursday that their investigation centres on "public comments that some jurors could have allegedly made before the jury began".

At least one of the jurors is also suspected of having used a mobile phone during the trial, reports said.

Those arrested on Thursday were questioned at the Financial Crime Investigations Department before being released on police bail.

In a statement issued on Thursday evening, police urged caution over reports surrounding the investigation, stressing that it was focused "exclusively" on the oath taken by jurors before the trial began.

Police said the investigation was "not on any other theory or allegation that may have been reported in the media."

Fenech was acquitted earlier this month of complicity in the wilful homicide of Caruana Galizia and association with another person or persons for the purpose of committing a crime in Malta.

The nine-member jury returned an 8-1 not guilty verdict on both counts on 2 September, after deliberating for just over eight hours.

The verdict followed 55 days of proceedings, during which jurors heard extensive evidence concerning the assassination and the events surrounding it.

The prosecution is expected to appeal the verdict and seek a retrial on grounds concerning the jury trial process. Such an appeal would be decided by a three-judge court.

The Attorney General has a 15-working-day window from the verdict to file an appeal.