Train carrying bodies of MH17 victims arrives in Ukrainian-controlled city

Kharkiv, Ukraine (CNN) -- A train carried the remains of most victims from Malaysia Airlines Flight 17 from the crash site in rebel-controlled territory to a government-controlled city Tuesday -- getting the bodies one step closer to their grieving families around the world.

The train traveled from the crash site in rebel-controlled eastern Ukraine and arrived at a rail station in Kharkiv and were taken to a closed military area, where the 282 bodies will be put in coffins flown in from the Netherlands.

The bodies will eventually be taken to the Netherlands, where most of the passengers were from.

But a litany of obstacles remain -- not just in handling the remains, but in figuring out how and why MH17 was shot down over eastern Ukraine.

Five days after the the plane carrying 298 people plunged from the sky, here's the latest:

The victims

As authorities wait to process the 282 bodies, the remains of 16 people were still missing as of Monday, Ukrainian President Petro Poroshenko told CNN's Christiane Amanpour.

The Ukrainian government has said 87 "body fragments" had been recovered from the sprawling crash site, but it's unclear who they may have belonged to.

The grisly scene was marred by reports that pro-Russian Ukrainian rebels, who control the area, had looted personal items from the scene and prevented international investigators from entering.

Poroshenko said the rebels' conduct was "barbaric."

But Dutch forensics experts who inspected the train Monday were "more or less" satisfied with how the bodies were being stored," said Michael Bociurkiw, the spokesman for monitors from the Organization for Security and Co-operation in Europe.

The remains will be flown to Amsterdam on board a Dutch C-130 Hercules, officials said.

An Australian plane will also be involved in taking the bodies from Ukraine to Holland, Australian Prime Minister Tony Abbott said Tuesday.

Dutch Foreign Minister Frans Timmermans said bringing the victims' remains home is his country's top priority.

"To my dying day, I will not understand that it took so much time for the rescue workers to be allowed to do their difficult jobs," he told the U.N. Security Council on Monday, "and that human remains should be used in a political game."

The 'black boxes'

Ukrainian rebels gave Malaysian officials the data recorders from downed Flight 17 on Tuesday after days of attempts by the Malaysian government.

"In recent days, we have been working behind the scenes to establish contact with those in charge of the MH17 crash site," Malaysian Prime Minister Najib Razak said early Tuesday morning.

Najib said he spoke with rebel leader Alexander Borodai and reached an agreement for the transfer of the black boxes.

Malaysian officials will keep the black boxes while an international investigation team is being formalized, Najib said.

Once the team is finalized, "we will pass the black boxes to the international investigation team for further analysis," he said.

The voice recorder could include audio from the cockpit, which would show whether the pilots knew the plane had been hit, said Mary Schiavo, a CNN aviation analyst and former inspector general for the U.S. Department of Transportation.

And the flight data recorder will give investigators information about engine settings, pressurization and electronic communications, among other details, she said.

But even the black boxes might not answer the two most pressing questions: who shot down the plane, and why.

The blame game

The U.N. Security Council adopted a resolution Monday demanding full access to the crash site and condemning the downing of the plane.

The resolution won unanimous approval from the 15-member council, which includes Russia. It did not specify who was responsible for the crash.

U.S. and other officials have said it appears the plane was shot down by a sophisticated surface-to-air missile located within rebel-held territory. Evidence supporting that conclusion includes telephone intercepts purporting to be pro-Russian rebels discussing the shootdown and video of a Buk missile launcher traveling into Russia with at least one missile missing.

Obama, British Prime Minister David Cameron and others have said the pro-Russian rebels could not have shot such a high-flying jet down without weapons and training from Russia.

Obama called on Russia to rein in the rebel fighters, who he said had treated remains poorly and removed evidence from the site.

"What exactly are they trying to hide?" he said.

Officials said Monday that U.S. intelligence analysts are examining phone intercepts, social media posts and information gathered on the ground to see if Russian officials played a direct role in the shootdown, according to two U.S. officials directly familiar with the latest assessment. The officials declined to be identified because of the sensitivity of the situation.

"We are trying to determine if they manned it, advised, or pulled the trigger," one of the officials told CNN.

Pro-Russian rebels have repeatedly denied responsibility for the attack.

"This is an information war," Borodai said. "We don't have the technical ability to destroy this plane. Ukrainians are not interested in the truth."

Moscow has strongly denied claims it pulled the trigger. Russian Army Lt. Gen. Andrei Kartapolov suggested a Ukrainian jet fighter may have shot the plane down.

Russian monitoring showed a Ukrainian Su-25 fighter jet flying along the same route and within 3 kilometers to 5 kilometers (1.9 miles to 3.1 miles) of Flight 17, Kartapolov said, according to Russian state media.

"We would like to know why the Ukrainian plane was flying along a civilian route on the same flight path as the Malaysian Boeing," Kartapolov said, according to the reports.

In his interview with Amanpour, Poroshenko rejected the Russian suggestion, saying all Ukrainian aircraft were on the ground at the time.

Vitaly Churkin, Russia's ambassador to the United Nations, also blamed Ukraine for the crash on Monday. But when asked about audio recordings purporting to show pro-Russian separatists talking about shooting down a plane, he suggested that if they did, it was an accident.

"According to them, the people from the east were saying that they shot down a military jet," he said. "If they think they shot down a military jet, it was confusion. If it was confusion, it was not an act of terrorism."

Ukrainian President: The world must choose sides

So much we don't know -- eight unanswered questions

Who were the victims?