What brought down Malaysia Airlines Flight 17 is already known. A Soviet-era surface-to-air missile fired from separatist-held territory in eastern Ukraine tore the Boeing 777 apart as it cruised more than 10 kilometres above the Donetsk region.
An international criminal probe is under way that could uncover terrorism, or perhaps war crimes, if Russia, Ukraine or both are implicated in events leading up to the attack, which killed 298 people.
The flight data and cockpit voice recorders – usually crucial in air crash probes – will likely reveal little. The pilots probably never saw the five-meter, needle-nosed radar-guided missile approaching at three times the speed of sound. When its proximity fuse fired the 70 kilograms of high explosive, metal bars whirling like scythes would have sliced though the airliner in a fraction of a second. The recorders will likely show everything was normal one second and then just stopped.
Still, a search is on, complicated by political posturing and the grim reality that debris and bodies are scattered across a war zone. The probe must determine who fired the surface-to-air missile (SAM), then nail down the source, and what role, if any, Moscow and Kiev played.
The evidence includes U.S. intelligence from a spy satellite that detected the missile launch, a rebel claim minutes after the crash that a Ukrainian military transport had been hit, an intercepted radio exchange in Russian between two separatist commanders that "Cossacks," as the rebels style themselves, had shot down an aircraft. It all indicates the attack came from a tracked BUK SA-11 launcher – dubbed Gadfly by NATO – in rebel-held territory.
"The plane was shot down by a surface-to-air missile that was launched from an area that is controlled by Russian-backed separatists inside of Ukraine," U.S. President Barack Obama said delivered a statement on Friday.
On June 26, separatist rebels claimed they had a BUK from a Ukrainian military base. The boast was backed by photos of the mobile launcher with four-missiles on top. Other photos – since erased from rebel internet accounts – show the green SA-11 unit and missiles near the suspected launch site, including one taken next to an apartment building in Snizhne, a town where Ukrainian warplanes bombed rebel positions earlier this week.
Immediately after contact was lost with Malaysia Flight 17, a rebel commander, Igor Girkin,, using the nom de guerre Strelkov, posted online: "In the vicinity of Torez, we just downed a plane, an AN-26 [Antonov-26]. Its wreckage landed near Progress Mine. We have issued warnings not to fly in our airspace."
In the past few weeks, Russian-backed separatists shot down a Ukrainian air force Antonov-26 transport plane and at least two Ukrainian Mi-8 military helicopters.
"These separatists have received a steady flow of support from Russia," Mr. Obama said. "This includes arms and training. It includes heavy weapons, and it includes anti-aircraft weapons."
The back story gets murky, especially where it concerns Russia and Ukraine.
The Ukraine military would know if it lost an SA-11 with at least four operational missiles more than three weeks ago. Then, three days before Flight 17 was shot down, a Ukrainian AN-26 transport was shot down by a missile in the same area. It was flying at 7,000 to 8,000 metres – far above the reach of man-portable missiles (manpads).
If the Ukrainian military knew it lost a SAM system, Kiev will face tough questions on why it allowed commercial airliners to continue flying over an area where it knew insurgents had used surface-to-air missiles capable of destroying aircraft at high altitudes. Dozens of commercial planes flew from Europe to Asia on routes matching that of MH17 in the days before the incident.
"The circumstances surrounding the actual firing are still uncertain, but several factors are important. Ukraine did not issue a warning notice about risk to civilian airliners after the AN-26 was shot down," Anthony Cordesman, a senior defence analyst at the Center for Strategic and International Studies in Washington, said in an analysis published on Friday.
That Kiev left the airspace open and did not issue a warning will be seen by some as inexplicable, if not as complicity.
Even murkier is whether, and to what degree, Russia was involved.
On June 30, four days after the rebels reported they had a BUK, NATO's Supreme Allied Commander, General Philip Breedlove, told a Pentagon news conference Russia was training the separatists to use vehicle-mounted surface-to-air missile systems. "What we see in training on the east [Russian] side of the border is big equipment, tanks, APCs, anti-aircraft capability, and now we see those capabilities being used on the west side of the border," he said. Asked if Russian SAM launchers had been sent into Ukraine, he said: "We have not seen any of the air defence vehicles across the border yet, but we've seen them training in the western part of Russia."
The Soviet-era BUKs were designed to be operated with fairly rudimentary training, and thousands of former military personnel – including some pro-Moscow separatists – in the Ukraine probably have experience with them. Both the Ukrainian and Russian militaries have them, but the direct confirmation by NATO's top general, an American with access to U.S. intelligence, that the rebels were getting Russian training on BUK launchers points powerfully at Moscow, even if the actual launcher was from the Ukrainian military.
"We have not seen training of manpads, but we have seen vehicle-borne capability being trained," Gen. Breedlove said.