Although the site may have been compromised, experts say there will likely be enough evidence and clues scattered about to get answers about the crash, even if the rebels have attempted to hide the cause.
“I never say never about anything, but I kind of doubt they could identify and find all the pieces,” said Richard Marquise, a former FBI agent who led the task force investigating the bombing of Pan Am Flight 103 over Lockerbie, Scotland. “I mean, if they sent a team of 1,000 people there, let's presuppose it was the Russians … they might be lucky to pick up every single piece and walk away with it, but I think in a huge crime scene it’s very difficult.”
So far, separatists have given international observers only limited access to the crash site. On Monday, U.S. President Barack Obama accused the separatists of impeding the investigation and removing evidence. “What exactly are they trying to hide?” he asked.
Rebels have handed over two black box flight recorders to aviation experts, which could provide some information. Or, as in the case of Pan Am Flight 103, they might only reveal that a catastrophic failure on the aircraft occurred. This is why debris from the wreckage of planes often provides crucial clues into the cause of crashes.
In the case of the bombing of Pan Am Flight 103, forensic specialists found framing from an aluminum baggage container marred with the residue of high explosives. This allowed investigators to determine quickly that a bomb had brought down the plane, Marquise said.
Fragments from the fuselage also revealed that the blast did not come from outside the aircraft. Meanwhile, investigators found on the ground a tiny fragment “no bigger than a thumbnail” that came from a radio/cassette player that had been used to store the bomb, and a fragment from a timer that could be traced to Libya.
Unlike Lockerbie bombing case
The case of Flight MH17 is different, if it was a missile that brought down the Boeing 777. Wreckage of the plane, which might be scattered over kilometres, would be important to determine whether the plane was downed by an external force.
"If it was an explosive device, what the investigators would be looking for is evidence of that explosive device,” said Phil Giles, who worked in Britain's Air Accidents Investigation Branch and was part of the Lockerbie bombing investigation team "That’s all stuff that, with people poring over the site, can get trampled on, moved. Whereas with this [crash] you’re really in a different scenario.”
“Once you found some evidence like big holes in the side of an airplane, which indicates a rocket has gone off near it, you’re not that interested in finding the timing mechanism of the rocket.”
Forensic investigators will try to locate the outside skin of the airplane and see if they can prove that something went into the fuselage. If the missile didn’t directly hit, but detonated at a point near the fuselage up next to the lower end of the cockpit, investigators should still find metal deformed inward, said Billie Vincent, former head of security for the Federal Aviation Administration. As well, anything exploding near a metal object is going to leave minute particles from the explosive.
Difficult to conceal missile fragments
If it was a missile, obviously finding those fragments is key. Giles said many of those fragments may not end up in the same place as the aircraft. But there could be bits and pieces embedded in parts of the wreckage and in some of the dead passengers, making it unlikely anyone could walk away with all the evidence.
“If it’s a missile, I don’t think they will have done enough to actually conceal that fact, because it‘s going to be so damaged and there’s going to be so much evidence of the damage from the shrapnel going through the airplane,” Giles said.
Once those missile fragments are identified, they would be given to experts in missile technology and forensics to try to figure out the make, and possibly, trace its history.
"I've seen these things for decades, where somebody can go back and trace who ordered these things, who were these made for, who was the customer," Marquise said. "I think they have a pretty good chance of figuring out these were made for this government, by this company and sold on this date. I think there's an awful lot of things, if they find some fragments of what we all think is probably a missile."
However, Vincent said, if the separatists are smart enough and grab the right pieces of the airplane, where the missile impacted or detonation occurred, they could still stymie the investigation.
"The question on this point will probably depend on the sophistication of the people they have out, those rebels, and the level of expertise the Russians bring in to try and find those things and confuse the environment."
But Marquise said he remains "cautiously optimistic" that if real investigators get to the site in the next couple of weeks, they will be able to find something that will "at least tie back to some group, country, whatever, where the world can make a political and diplomatic case that this is the government that is responsible."