Yorgen Fenech was arrested for a fourth time on Wednesday by police investigating the murder of journalist Daphne Caruana Galizia, according to sources involved in the case. 

Mr Fenech, a prominent businessman who until his arrest last week led the Tumas Group as CEO, is being questioned by investigators who want to glean further details about the 2017 murder. 

They now have until Friday afternoon - 48 hours - to press charges against him, release him without charges or on police bail. 

Police set up a netted screen to hide the view into their Floriana headquarters, as media interest in the Caruana Galizia case mounts.

Mr Fenech is, however, angling for a fourth option – being granted a presidential pardon in exchange for information about the crime and others. 

He has told investigators that he has incriminating information about the Prime Minister’s former chief of staff Keith Schembri and also alleged that Mr Schembri was passing him concealed messages while he was in custody last weekend, through a doctor who knows both men. 

The doctor, named as Adrian Vella, is also under arrest, Times of Malta reported earlier on Wednesday. 

The 48-hour period Mr Fenech can be held for will expire some hours after a middleman in the murder case, Melvin Theuma, is expected to testify before a magistrate. Mr Theuma has been granted immunity from prosecution in exchange for information.

Earlier on Wednesday, Ms Caruana Galizia's family requested an urgent meeting with the attorney general "to clarify the situation around Yorgen Fenech's request for a presidential pardon". 

Mr Fenech was first arrested last Wednesday as he was exiting Portomaso marina aboard his yacht. He has since been released three times, with police rearresting him a short while later each time. 

Last week, Prime Minister Joseph Muscat told the press that the police had opted for that course of action as they needed more time to interrogate Mr Fenech.