May 24 (UPI) -- A missile that shot down Malaysia Airlines Flight 17 over eastern Ukraine four years ago came from a launcher belonged to the Russian military, investigators said Thursday.
A Boeing 777, MH17 was flying over Ukrainian airspace on July 17, 2014, when it crashed and killed all 298 aboard. It was headed from Amsterdam to Kuala Lumpur.
The Joint Investigative Team -- which includes authorities from Australia, Belgium, Malaysia, the Netherlands and Ukraine -- said in a statement the missile system used to shoot the airliner was owned by Russia's 53rd anti-aircraft military brigade.
Officials said the information backs earlier findings that the BUK missile system was taken from Russia to Ukraine and back after the attack, and that the launch site was an agricultural field controlled by pro-Russian fighters.
"At the time, this area was under control of pro-Russian separatists," said Fred Westerbeke of the National Prosecutor's Office of the Netherlands.
The prosecutor added the findings raises questions as to whether the brigade was "actively involved in downing MH17." He said also the team's investigation is not yet complete.
"That a sophisticated weapon belonging to the Russian Army was dispatched and used to shoot down a civilian aircraft should be of grave international concern," the investigators said. "We are discussing these findings with our partners and considering our options."
Russia has denied shooting down MH17, instead blaming Ukrainian forces for attack.
The downing of MH17 came about four months after Malaysian Airlines lost another Boeing 777, Flight 370, which disappeared over the Indian Ocean after leaving Kuala Lumpur for Beijing. It has never been found and all 239 on board are presumed dead.