After a painstaking 15-month investigation, the Dutch Safety Board has published its final report into what caused Malaysia Airlines Flight 17 to break up high over Eastern Ukraine last year, killing all 298 people on board.

As expected, the probe concluded that a Buk surface-to-air missile downed the plane and it identified a 320 square-kilometer (123 sq. mile) area of the conflict-torn region from which the missile must have been launched.

Russian authorities dismissed the report's main findings.

WHAT DID TUESDAY'S REPORT SAY HAPPENED?

It could not have been more clear. The flight heading from Amsterdam to Kuala Lumpur was flying over Eastern Ukraine when a "9N314M warhead, launched by a Buk surface-to-air missile system" detonated just above the cockpit, spraying the front of the Boeing 777 with "hundreds of high-energy objects" from the warhead. The blast killed the three crew members in the cockpit instantly and caused the plane to break up in midair and plummet to earth. Wreckage was spread over a 50 square-kilometer (19 square-mile) area on the ground.

There's no doubt? Not according to the Dutch Safety Board, which said in a statement that other possible scenarios such as an explosion inside the plane or an air-to-air missile "have been investigated and excluded. No scenario other than a Buk surface-to-air missile can explain this combination of facts."

WHAT DOES RUSSIA SAY?

Russian deputy foreign minister Sergei Ryabkov said of the report that the "attempt to make a biased conclusion, in essence to carry out a political order, is obvious."

Even before the Dutch report was released, the Russian maker of Buk missiles presented its own report trying to clear Russian-backed separatists, and Russia itself, of any involvement. Almaz-Antey contended that its experiments — in one of which a Buk missile was detonated near the nose of an airplane similar to a 777 — contradict that conclusion. The experimental aircraft's remains showed a much different damage pattern than on the remnants of MH17, the company said in a statement.

WHAT OTHER CONCLUSIONS DID THE DUTCH INVESTIGATION REACH?

The report also said that the tragedy could have been avoided if Ukrainian authorities had thought to close their air space because of the conflict raging on the ground. The safety board's chairman, Tjibbe Joustra, said that, "Our investigation showed that all parties regarded the conflict in eastern part of Ukraine from a military perspective. Nobody gave any thought of a possible threat to civil aviation."

The board said that states, international organizations and airlines should "exchange more information about conflict areas and potential threats to civil aviation."

The report also criticized Dutch authorities for their handling of the passenger lists in the aftermath of the disaster — it took up to four days for all relatives to get confirmation their loved ones were on the doomed flight. It said, "The Dutch crisis organization failed to function properly and the government authorities involved lacked direction."

WHAT DID THOSE ON BOARD KNOW ABOUT THE MISSILE STRIKE?

The three crew members in the cockpit were killed instantly. As the plane broke up, the other 295 people on board were subjected to factors including decompression, extreme cold, strong air flows and objects flying around what was left of the cabin. However, the board added that "It is likely that the occupants were barely able to comprehend the situation in which they found themselves."

WHAT DID TUESDAY'S REPORT NOT SAY?

Who did it. The Dutch Safety Board investigation was not aimed at establishing who exactly blew the plane out of the sky, only how it happened. A separate criminal investigation is underway that is aimed at identifying the perpetrators and bringing them to justice. Prosecutors said Tuesday their investigation will stretch into next year.

IF SUSPECTS ARE IDENTIFIED, WHERE WILL THEY FACE JUSTICE?

That crucial question remains unanswered. Countries whose citizens were killed, including the Netherlands, Malaysia and Australia, want to set up an international tribunal to prosecute any suspects. Russia vetoed the move earlier this year at the United Nations Security Council. Ukraine's foreign minister said in July that a fresh attempt would likely be made to establish a tribunal once the final report is published.

HOW DID FAMILIES OF VICTIMS REACT?

It was tense and emotional in a Hague congress center as Joustra told relatives the report's conclusions and showed an animation of the plane's last moments, said Rob Fredriksz, whose son Bryce died.

Barry Sweeney, whose son Liam died on MH17, said he hoped that those on board did not suffer.

"We don't really know," he said. "We're just hoping, and I've got to believe, that Liam and the other 297 people died instantaneously."