HRABOVE, Ukraine – When international monitors and Malaysian aviation experts arrived Tuesday at the two main sites where the wreckage of Malaysia Airlines Flight 17 smashed into the undulating countryside of eastern Ukraine, there was almost no perimeter tape.
The only security consisted of two armed men who did not stop reporters from walking across the fields to the twisted metal.
Amid the stench of decay and buzzing flies, one piece of the Boeing 777's fuselage that had previously been lying on the ground was propped up against a post.
The lack of security and images of separatist rebels rifling through the wreckage in the days after last Thursday's crash killed all 298 people aboard are an investigator's worst nightmare and have stirred fears that vital evidence was contaminated or may have disappeared altogether, hampering efforts to piece together exactly what happened to the doomed flight.
"We are keeping a very close eye on that," said Michael Bociurkiw, a spokesman for the Organization for Security and Cooperation in Europe. "Looking at the fuselage now compared to what it was on Day One. And we have noted some differences."
A day earlier, Bociurkiw reported seeing workers "hacking into the fuselage with gas-powered equipment."
Experts say a cardinal rule of investigations has been breached.
"The crash site is a crime scene and, as everyone knows, you don't mess with crime scenes," said Justin Green, an aviation industry lawyer in New York and former military pilot and crash investigator. "This crime scene has been disturbed. Quite substantially disturbed."
Airline disaster investigations have two main strands — identifying the victims and establishing what happened. In this case, the U.S. and its allies believe the plane was shot down with a missile fired by pro-Russian separatists.
Identifying the victims ought to be relatively straightforward. Some can be visually identified by relatives, through distinguishing features such as tattoos or scars, or by the use of dental records. For bodies torn apart in the disaster, DNA analysis should provide grieving families with definitive evidence their loved ones have been found.
For days, Dutch police officers have been visiting the bereaved across the Netherlands — home to 193 of the dead — seeking information about distinguishing features and collecting DNA samples for use in identifying the remains. That process will start Wednesday at a military barracks in the Dutch town of Hilversum, after the first planes carrying remains arrive in the Netherlands on a national day of mourning.
Jos van Roo, leader of the Dutch national forensics team that will undertake the painstaking task, said Tuesday he wants to identify all victims.
"That's always our goal," he said.
But investigators have to find all the victims before they can be identified. There were conflicting reports Tuesday night about how many bodies had been collected and put on a train that ground slowly through rebel-held territory and into the government-controlled town of Kharkiv. Estimates ranged from around 200 to more than 280 bodies.
"The delay and fact that they have not accounted for the right number (of bodies) causes me concern that they got started so late and started so badly that some families may never recover their loved one," Green said.
Anthony Busuttil, chief pathologist in the investigation into the 1988 bombing of a Pan Am jet over Lockerbie, Scotland, said a surprisingly large number of bodies could be intact despite plunging tens of thousands of feet to the ground. Identifying them should not be a problem, he said.
But methodically establishing exactly what happened to the flight will be harder, given the way the evidence has been handled.
"Bits of the plane, bodies, property from the bodies, property from the plane, were being picked up willy-nilly," he said. "We don't know where the bodies have been — there's a stick in the field where they were found or what have you. There's no accuracy. There's no continuity. There's no detail."
Green said the critical evidence is probably going to be coming from the military and intelligence community.