Investigators over the past few hours continued to interrogate 'other' people in connection with the Daphne Caruana Galizia murder investigation, the police said in a brief statement on Tuesday morning.

"The investigations are continuing" the statement read. No details were issued on who the 'other' persons were.

Yorgen Fenech, the 'person of interest' arrested last week after his yacht was intercepted as it sailed out of Portomaso, remains under arrest, having been released and re-arrested three times as the police struggled with the 48-hour 'arraign or release' condition laid down by law.

Also undergoing further interrogation is Melvin Theuma, the suspected middleman in the murder plot, who was granted a presidential pardon to reveal all his information on Monday evening.

Fenech too has requested a pardon to reveal information. The request is still being considered by the prime minister. 

The Caruana Galizia family last week insisted that the prime minister distance himself from the investigations in view of Fenech's connections to senior government figures, particularly chief of staff Keith Schembri and minister Konrad Mizzi.

As pressure grew, even within the Labour Party, for Mizzi and Schembri to go, the minister on Monday defiantly said he would fight on and denied any wrongdoing. Schembri refused to comment to the press as he walked into the Auberge de Castille.

Net News reported on Tuesday that Schembri had a long meeting with Prime Minister Muscat at the latter's Burmarrad residence on Monday-Tuesday night.