Updated 2.50pm, adds PD statement
Prime Minister Joseph Muscat said on Thursday he hoped investigations into the Daphne Caruana Galizia murder will be completed in the next few hours.
Questioned as to whether he fears his office had blood on its hands, amid the most recent developments, Dr Muscat said he could not comment and would only be able to comment once investigations are over "hopefully in the next few hours."
The prime minister's former chief of staff, Keith Schembri is still being interrogated as a person of interest in the murder investigation.
His arrest came after businessman Yorgen Fenech, arrested a week ago, requested a pardon and named Mr Schembri as the alleged murder mastermind.
The police are also continuing to question Melvin Theuma, the suspected middleman in the plot, who has been granted a pardon in return for information.
Mr Theuma is expected to testify on Thursday evening before the magistrate conducting the Caruana Galizia murder inquiry.
He is also expected to be called to testify in the compilation of evidence against three men who have been behind bars since December 2017 and are awaiting trial for having allegedly set off the bomb which killed Ms Caruana Galizia on October 16, 2017.
In a statement later, Partit Demokratiku said the Prime Minister's assertion that investigations into Daphne was cause for tremendous alarm.
"Independent investigations do not wrap up when it is most politically crucial or convenient. Any investigation into the assassination that ends on Muscat's watch must be deemed compromised. Muscat must resign."
PD said the Prime Minister's role in the investigations must be questioned, and the pardon given to Melvin Theuma must now be put into doubt.
"The pardon was given while Keith Schembri was still chief of staff. Was it pre-arranged to pin all of the blame on Yorgen Fenech, to exonerate Keith Schembri? Where is the Police Commissioner? Why have police not investigated Castille, where Keith Schembri operated with impunity as Chief of Staff," PD asked.
Partit Demokratiku warned against allowing the Prime Minister to meddle and hide the truth, which would only prolong the national suffering and lead to further conflict.
"The Prime Minister must resign and an interim Prime Minister elected to preside while the investigation runs its course," PD insisted.