The family of murdered journalist Daphne Caruana Galizia has called for a full public inquiry into her death, accusing Maltese authorities of failing in their duty to determine whether more could have been done to save the reporter’s life.

Ms Caruana Galizia, who had probed money-laundering and corruption in the Mediterranean island nation, was killed when a bomb destroyed her car on October 16 last year. She was 53.

Three Maltese men have been ordered to stand trial for murder. Investigators believe that the men were working for someone, but no controlling figure has yet been identified.

The journalist’s son, Paul Caruana Galizia, told the BBC that the probe into her death was too narrow, focusing simply on how she died rather than who was behind it.

He said he wants an inquiry into the actions of what he called Malta’s “mafia state”.

On Thursday, Mr Caruana Galizia delivered a legal opinion prepared by UK lawyers to a Malta’s High Commission in London.

The document said Malta’s government has failed in its “investigative duty”.

It argues that “Malta has failed to institute any form of inquiry into the wider circumstances of Ms Caruana Galizia’s assassination”, or whether her life could have been saved.

Tony Murphy, one of the family’s UK-based lawyers, said Ms Caruana Galizia’s family wants Maltese authorities to establish an independent board of inquiry made up of Maltese and international judges.

He said state involvement in the journalist’s death has not been proven, but the family “certainly can’t rule it out given that the chief targets of Daphne’s criticism in her writing and journalism were senior politicians”.

He urged Maltese authorities to agree to an inquiry, adding: “Malta has nothing to fear but the truth.”

Mr Murphy said the family is giving Malta’s government until August 31 to respond.

If Malta fails to act, the family plans to take action in the Maltese courts and possibly at the European Court of Human Rights.