Not all passengers on board Malaysia Airline flight MH17 appear to have died instantly, according to Dutch Foreign Minister Frans Timmermans, who said Thursday that one of the 298 people killed in eastern Ukraine skies in July was found wearing an oxygen mask.

The oxygen mask was found secured around the neck of an Australian citizen, said Wim de Bruin, a spokesperson for the Dutch National Prosecutor's Office, which is leading investigations.

Dutch forensic experts investigated the mask for fingerprints, saliva and DNA, said de Bruin, but no results were produced. Dutch prosectors said they don't know "how or when the mask got around the victim's neck," according to the Associated Press, and no other MH17 victim was found with an oxygen mask on.

Timmermans acknowledged that no passenger would have seen the missile coming.

"People hardly had time to notice the missile coming, but do you know that one of the victims was found with an oxygen mask over their mouth?" Timmermans said Thursday.

"This means that someone had time to do that," he said. "At least, we cannot rule out this possibility."

Former top Russia test pilot Magomed Talboev told Slon.ru that finding on MH17 passenger with an oxygen mask doesn't invalidate previous assumption about the immediate death of everyone on board.

"A couple of seconds could pass before the plan disintegrated. This is enough to grab a mask that falls automatically in front of your face and put it on - this is [survival] instinct."

A preliminary report from the Dutch Safety Board said MH17 had its fuselage pierced by large numbers of "high energy objects" on July 17 before breaking up in midair. The report claimed everyone died immediately due to decompression, and made no mention of the use of oxygen masks.

Only 251 victim bodies have so far been identified by Dutch officials.