The missile that downed flight MH17 over eastern Ukraine was transported from Russia, a criminal inquiry revealed Wednesday, as it announced that about 100 people were being investigated for playing "an active role" in the disaster.
Saying they had "irrefutable evidence" that the BUK missile system was used to blow the Malaysia Airlines plane out of the sky, investigators also for the first time pinpointed that the device was fired from a field in a part of eastern Ukraine then controlled by pro-Russia separatists.
The findings of the Dutch-led probe stopped short of directly accusing Moscow of involvement in the tragedy in July 2014, and both the rebels and Russia issued fresh statements denying any responsibility.
But the new details appeared to back up long-standing accusations from Ukraine and the West that pro-Russian rebels were to blame using a missile which may have been provided by Moscow.
The Boeing 777 was ripped apart mid-air during a flight from Amsterdam to Kuala Lumpur over Ukraine, where a war pitting separatists allegedly armed by Russia against the Kiev government erupted in April 2014.
All 298 people on board the plane including 196 Dutch citizens were killed.
But despite two official international investigations, the burning question of who gave the orders and who pulled the trigger remain unresolved.
Ukrainian President Petro Poroshenko hailed the inquiry's initial findings saying: "We have solid proof of who is to blame for this dreadful crime and who bears full responsibility for the terrorist attack."
- Phone taps -
A "BUK missile from the 9M38-series" was used that "came from the territory of the Russian Federation," said Wilbert Paulissen, the head of the Dutch police investigation.
When it reached Ukraine it was transferred onto a white Volvo truck and escorted by armed men in uniform. Afterwards the missile launcher system "was taken back to Russia," Paulissen said.
Over the past two years, up to 200 investigators have studied half a million photos, videos, some 200 witness statements and 150,000 tapped telephone conversations.
They have also assessed five billion internet pages to painstakingly retrace the route taken by the convoy which brought the missile system into eastern Ukraine.
In one chilling wiretapped phone conversation from July 16, 2014 played to reporters on Wednesday, one man believed to be a Russian-speaking military commander asks another if he can "receive a BUK in the morning" saying his forces are under pressure from air strikes and he doesn't know if "they can hold on."
The 700-kilogramme (1,500-pound) BUK, a complex radar-guided ground-to-air anti-aircraft weapon, was fired from a field in Pervomaiskyi which at the time "was in the hands of the Russian separatists," said Paulissen.
The joint investigation "has identified approximately 100 people" believed to have had an "active role" in transporting the missile system, added chief investigator Fred Westerbeke.
Moscow, which remains under EU sanctions for its alleged role in the Ukrainian conflict, has always denied being part of the MH17 disaster. It described the inquiry as "biased" and "politically motivated" saying it was "disappointed" by the results.
Ukrainian rebels also quickly rejected any conclusion that they were behind the disaster.
"The forces of the People's Republic of Donetsk could not have fired at the plane from a BUK system because we have no such sort of weapons," general Eduard Basurin of the self-proclaimed republic told AFP.
But Dutch prosecutors later released the names of two men heard speaking Russian in a wiretapped conversation, saying they wanted more information about them.
"What is clear is that the BUK missile system came from Russia to Ukraine, was fired and taken back to Russia," Piet Ploeg, who lost three relatives in the disaster, told AFP.
The findings "clearly suggest the involvement of the Russian Federation," he added.
- 'Cowardly assassins' -
The criminal investigation has now been extended to 2018, but Westerbeke said he could make "no promises" about when any suspects would be brought to justice.
"The relatives have run out of patience. They want these cowardly assassins to be brought to justice," Evert van Zijtveld, who lost his 18-year-old son Robert-Jan and daughter Frederique, 19, and his parents-in-law, told the Dutch broadcaster NOS.
Dutch Prime Minister Mark Rutte called the preliminary findings "an important step on the road to the ultimate goal: finding and prosecuting the perpetrators."
And Malaysian Prime Minister Najib Razak said his country sought "firm action" so that those responsible "will be brought to justice."
Should any Russian suspects be identified however, the chances are small that they'd be prosecuted, as the Russian constitution expressly forbids Moscow from extraditing its citizens to another country.