Relatives of victims of the MH17 tragedy have been told that a Dutch-led investigation found proof that a mobile Buk missile launcher had been moved into eastern Ukraine from Russia at the time.
Hans de Borst, whose 17-year-old daughter was among the 298 people that perished when the Malaysia Airlines flight was downed, said he and other family members were briefed privately on Wednesday morning before a news conference scheduled to announce the preliminary results of a Dutch-led investigation into the causes of the disaster.
He said the investigators said they had proof, including communications intercepts and radar data, that a mobile Buk missile launcher had been moved into eastern Ukraine from Russia.
He says investigators said the launcher was moved back into Russia after the Boeing 777 was downed.
The conclusions were billed as results of a two-year Dutch-led criminal probe of the disaster that claimed 298 lives.
Thomas Schansman, father of the only US citizen killed in the July 2014 disaster, said earlier that he expected investigators to identify which specific weapon they believe destroyed flight MH17, and where it was fired from.
He said family members do not expect investigators at this stage to name the people they believe were responsible.
A separate investigation by Dutch safety officials last year concluded that the Amsterdam-to-Kuala Lumpur flight was downed by a Buk missile fired from territory held by pro-Russian rebels.
Dutch police spokesman Thomas Aling said the joint investigation findings differ in that they are designed to be solid enough to be used as evidence in a criminal trial.
Where and when a trial might take place is still to be determined, Mr Aling said.
Russia has consistently denied allegations that pro-Moscow rebels in eastern Ukraine were responsible.