The body of one passenger on board Malaysia Airlines flight MH17 was found wearing an oxygen mask, Dutch prosecutors said on Thursday, raising questions about how much those on board knew about their fate when the plane crashed in eastern Ukraine in July.

The passenger, an Australian, did not have the mask on his face but around his neck, said Wim de Bruin, a spokesman for the Dutch national prosecutor’s office, which is carrying out a criminal investigation into the disaster.

De Bruin said Dutch forensic experts investigated the mask “for fingerprints, saliva and DNA and that did not produce any results. So it is not known how or when that mask got around the neck of the victim.”

De Bruin said no other bodies recovered from the wreckage were found wearing masks. He also said he did not know where in the plane the Australian victim was sitting.

All 298 passengers and crew died when the aircraft flying from Amsterdam to Kuala Lumpur crashed on 17 July. Dutch air crash investigators said last month it was probably struck by a number of “high-energy objects from outside the aircraft”, which some aviation experts say is consistent with a missile strike.

The head of the criminal investigation said the most likely of possible scenarios being investigated was that the Boeing 777 was shot down from the ground.

Relatives of the Australian passenger were told about the mask as soon as it was discovered, but families of other victims heard about it for the first time when the Dutch foreign minister, Frans Timmermans, mentioned it during an interview on a late-night talk show on Wednesday.

Relatives of victims began calling investigators on Thursday to ask about the comments, De Bruin said.

The foreign ministry issued a statement saying Timmermans regrets his comments.

“I have an enormous amount of sympathy for the next-of-kin,” he said. “The last thing I want to do is compound their suffering in this way.”