The missile that downed Malaysia Airlines Flight MH17 was fired from a Russian launcher in an area of Ukraine controlled by pro-Moscow rebels, a Dutch-led team of investigators and prosecutors concluded Wednesday.
The surface-to-air missile hit the Boeing 777 en route from Amsterdam to Kuala Lumpur killing 298 people in July 2014, breaking it apart in midair and scattering wreckage over several miles of fields.
At the time of the disaster, pro-Russian separatists were fighting Ukrainian government forces in the area.
Witness and social media evidence, along with intercepted communications, allowed investigators to track the Cold War-era Buk launcher being moved from Russia to rebel-held territory in Ukraine then back across the border after the disaster, the Joint Investigation Team (JIT) said.
Wilbert Paulissen, head of the Central Crime Investigation department of the Dutch National Police, said: "It may be concluded MH17 was shot down by a 9M38 missile launched by a Buk, brought in from the territory of the Russian Federation, and that after launch was subsequently returned to the Russian Federation."
The findings refute Moscow's suggestion that the plane was brought down by the Ukrainian military. On Monday, Russia said it had new data showing the missile did not originate from rebel-controlled territory and said it would turn the data over to investigators.
Russia's foreign affairs ministry spokeswoman dismissed the entire investigation as "biased and politically motivated."
Maria Zakharova said in a statement that investigators had "prevented Moscow from fully taking part in the … process."
"It sounds like an evil joke, but they've also made Ukraine a full member of the JIT, giving it the opportunity to fake evidence and twist the situation to its benefit," she said. "To this day, the investigation continues to ignore irrefutable proof presented by the Russian side, even though Russia is in fact the only country to send reliable information and reveal more and more new data."
Eduard Basurin, a defense spokesman for the separatist self-declared Donetsk People's Republic, told Interfax: "We did not have these air defense systems at our disposal — neither the systems, not the specialists [to operate it]. So we couldn't have shot down the Boeing."
Investigators also ruled out the possibility that MH17 was downed by another aircraft or by some kind of accident, but were unable to conclude whether the missile was fired at the passenger jet accidentally or deliberately.
Wednesday's report marks "an important milestone" in bringing to justice all those responsible for downing the aircraft, Ukraine's foreign ministry said.
Thomas Schansman, father of the only U.S. citizen killed in the July 2014 disaster, told The Associated Press he expected investigators to identify the weapon involved and where it was fired from, but not to name the people they believe were responsible.
Barry Sweeney, whose son Liam was among the dead, told the BBC: "It shouldn't have happened. To find out why it happened would be a bonus."
The inquiry concluded that the deadly surface-to-air missile was fired from farmland in the rebel-held area of Pervomaiskiy, 3 miles from the eastern Ukrainian town of Snizhne. Wednesday's news conference was shown pictures of scorched grass where the launch took place.
The downing played a significant part in a decision by the European Union and United States to impose sanctions on Russia over the Ukraine conflict, and East-West tensions escalated to levels not seen since the Cold War ended in 1990.
Russia-made Buk warheads, first built in the 1970s, are capable of shooting down aircraft up to 18 miles away. But the radar system that guides the missiles is designed for war zones, and is not capable of distinguishing between military and civilian planes.
Last year, a civil air accident investigation into the cause of the July 17, 2014 disaster by the Dutch Safety Board concluded that MH17 was downed by a Buk missile that exploded less than one yard from the aircraft's cockpit.
Hundreds of "high-energy" fragments pierced the fuselage, and the shrapnel instantly killed the two pilots and one crew member inside, it concluded. There was no time to make a mayday call or attempt to maneuver, the report noted.
"It was not possible to ascertain at which moment the occupants died," it added. "The impact on the ground was not survivable."