Maltese authorities must prosecute Keith Schembri for his "wide-ranging and long-running criminal activity" immediately, the family of assassinated journalist Daphne Caruana Galizia said in a statement on Tuesday.
The family was commenting a few hours after Prime Minister Joseph Muscat announced his chief of staff had resigned.
Sources have said that Mr Schembri was at police headquarters on Tuesday morning and was being questioned by investigators working on the Caruana Galizia case.
"Three years after our wife and mother revealed Keith Schembri’s financial crimes, two years after her assassination, Schembri has resigned as the Maltese prime minister’s chief of staff.
"We now urge the Maltese authorities to immediately prosecute Schembri for his
wide-ranging and long-running criminal activity. We urge Europol to provide the required, essential support to investigators, prosecutors and magistrates who are attempting to follow the money trail of the Malta-Azerbaijan money laundering network across jurisdictions, including especially the United Arab Emirates," the family said.
Ms Caruana Galizia's relatives also went on to urge the authorities to uncover why the Prime Minister had protected Mr Schembri and Tourism Minister Konrad Mizzi for three years.
"The failure to prosecute Schembri, Mizzi and their protectors had fatal consequences for our wife and mother. If that failure continues, it will have fatal consequences for Malta’s democracy."