murdered journalist Daphne Caruana Galizia
© Darrin Zammit Lupi/ReutersPeople hold up pictures of the assassinated journalist Daphne Caruana Galizia during a vigil and demonstration in Valletta, Malta, marking seven months since her murder.
The EU's top justice official is to fly to Malta this week to meet officers investigating the murder of Daphne Caruana Galizia after a report accused the authorities of seeking to delay and stall attempts to find those who wanted the journalist dead.

Věra Jourová, the commissioner for justice, is to seek assurances and ask "difficult questions" about the criminal investigation, which has been criticised by members of the European parliament.

A report from MEPs, on an "ad hoc mission" led by the German MEP Sven Giegold, has highlighted a series of concerns about the investigation, warning that the hunt for the journalist's killers appears to be in jeopardy. Caruana Galizia's son, Matthew, tweeted on Wednesday in response to the findings: "This is outrageous."

Jourová, the Czech Republic's representative in the commission, told the Guardian: "The issues in Malta go beyond this island, they concern the whole of the EU. My role, as a European justice commissioner, is to sometimes ask difficult and honest questions, especially on the issues that affect all of us.

"The commission expects an independent and thorough investigation to uncover who is really responsible for Daphne's murder, we want the full truth. There is no place in the EU for the murder of journalists."

The delegation of MEPs have warned in their report that the magistrate in charge of the investigation is being promoted and moved off the case, in a development that could slow down its progress.

They claim police are not following leads to discover the identity of those who ordered the car bombing that killed Caruana Galizia in 2017.

It is further claimed by the three MEPs sent to Malta on behalf of the parliament's political groups that officers have failed to "fully investigate" the witnesses who claim they saw Malta's minister of economy, Chris Cardona, drinking with one of three suspects being held on suspicion of detonating the bomb.

Cardona and his aide Joseph Gerada were suing Caruana Galizia for defamation over her claims that the pair had visited a brothel in Germany while on official government business. Her reports have been described by Cardona as "fabrications and lies".

Cardona has said that he only knew the suspects in her murder through his work as a criminal lawyer, but that he did not "recall having any discussions with any of these individuals, and have definitely never had any meetings with them".

Last year, a pre-trial hearing of evidence against the suspects, brothers Alfred and George Degiorgio and Vince Muscat, heard that the powerful car bomb used to kill Caruana Galizia was detonated by a mobile phone signal sent from a boat off the island's coast as part of a carefully planned operation lasting several months.

The three have pleaded not guilty to charges of murder, the criminal use of explosives, involvement in organised crime, and criminal conspiracy. However, there appears to have been little progress in discovering who ordered the crime.

The MEPs write: "The investigation on the assassination of Daphne Caruana Galizia is stalling. People we spoke to suspect that the plan may be to ensure the blame rests with the three suspected bombers and to eventually let them go free, after 20 months of detention."

"Magistrate Vella, who has been in charge of the murder investigation, has been offered a promotion to become a judge and should, in a few weeks, leave the case. This is interpreted by many as a way to delay and stall the investigation.

"The police is ostensibly not following all relevant leads to find out who ordered the assassination. Excuses provided go from lack of resources to impossibility to investigate all people exposed by the deceased who might have had a motive to silence her.

"Quite shockingly, the police appeared not to have thoroughly investigated witness accounts - published by international media - that minister of economy Chris Cardona had been seen drinking with one of the suspects prior to their arrest."

A spokesman for the Maltese government said the report had been drafted "by three MEPs after a visit to Malta in a private and political capacity, and not on behalf of the European Parliament or any of its committees". He accused the parliamentarians of making "wild allegations" which are "absolutely and completely false".

The spokesman said: "There is no evidence to support the theory that the investigation is 'stalling'. Three people have been arrested and charged with the murder of Daphne Caruana Galizia, and the investigation in to who ordered her murder carries on at pace. "Significant Police and Security Service resources are still deployed on the case."

It is understood that Jourová is to speak to Malta's minister for justice, Owen Bonnici, and the country's leading judge on Thursday, before meeting the officers investigating Caruana Galizia's murder. She is also due to lay flowers on the journalist's tomb.

Jourová said would also raise issues over Malta's offer of passports for cash and its flailing attempts to clamp down on organised crime and money laundering.

Jourová said: "I think the murder of a journalist was a wake-up call for many of us and a clear realisation that many things are related to one another. Money laundering, citizenship for sale, security, corruption are all part of the systemic threats to the rule of law and democracy as such."