VALLETTA: Maltese Prime Minister Joseph Muscat said Tuesday his chief of staff had resigned amid an ongoing probe into the murder of investigative reporter Daphne Caruana Galizia.

Sources said that the chief of staff, Keith Schembri, “was called in for questioning by police” on Tuesday after his name was mentioned by the main suspect in the case, Yorgen Fenech, who was arrested last week.

Caruana Galizia, a popular journalist and blogger in the Mediterranean island described as a “one-woman WikiLeaks,” was killed in a car bomb in October 2017 after exposing corruption involving high-level politicians.

The murder sparked outrage and protests, and Caruana Galizia’s family has accused Muscat of protecting those involved.

“I don’t know whether he is being questioned or what he is being questioned about,” Muscat told reporters when announcing Schembri’s resignation, the Times of Malta reported.

Schembri has served as Muscat’s chief of staff since 2013.

Leaked emails related to the Panama Papers data leak appeared to show that companies owned by Schembri and former energy minister Konrad Mizzi — currently the tourism minister — stood to receive payments from a Dubai company owned by mogul Fenech, 17 Black.

Caruana Galizia had written in her blog about 17 Black some eight months before her death.

Fenech, whose business interests span the energy to tourism sectors, was arrested on his yacht last week. He has requested immunity to reveal what he knows about the case. That decision is pending.

His arrest followed that of a middleman in the murder, Melvin Theuma, who on Tuesday was given immunity to expose those involved. Theuma is now expected to go before a judge to repeat what he has already told police.

Although three men face trial for carrying out the murder, the mastermind has never been identified.

Caruana Galizia’s family has said Muscat has “blood on his hands” for protecting Schembri and Mizzi.