The investigation into Daphne Caruana Galizia’s murder now involves a number of EU member states as “new concerns” emerge, Europol’s outgoing chief has said.

In a letter sent to MEP Ana Gomes, Europol executive director Rob Wainwright said “new concerns have arisen which are now the subject of further, high-priority investigation by Europol,” adding that it requires better cooperation by authorities in Malta.

The investigation was “highly complex and now involves a number of EU member states,” he said in the letter, dated 26 April.

Hinting that cooperation with Maltese authorities was not optimal, Wainwright said there was “there is some room for improvement in this cooperation and we are actively seeking to address this”.

In the letter to Gomes, who headed a European Parliament mission tasked to investigate the rule of law and money laundering in Malta, Wainwright  said Europol had no way of independently verifying the status of investigations and is completely reliant on information provided by Maltese authorities.

A government spokesman told members of the Daphne Project that Malta was cooperating with Europol “at every level” adding that it was willing to make “any improvements necessary” to improve cooperation.

On her part, Gomes described the letter as extremely serious because “it confirms that Europol has been involved with limitations, and here we are facing a government that has obviously been stalling investigations.”