Five days after a suspected surface-to-air missile downed Malaysia Airlines Flight 17 in eastern Ukraine, a team of three senior aviation experts from the airline itself finally reached the sprawling crash site, which stretches across 42-square-miles of territory held by pro-Russian separatists fighting an ongoing insurgency against the central government.
Earlier Tuesday, pro-Russia separatists handed the two black boxes from Flight 17 over to Malaysian investigators in the city of Donetsk. Malaysian Prime Minister Najib Razak said the handover was part of an agreement he had reached with rebel leader Alexander Borodai.
Najib said the black boxes appeared "to be in good condition."
Outrage has grown in the West over what appears to be a bungled start to the investigation. Rebels allowed a group of monitors from the Organization for Security and Cooperation in Europe (OSCE) only a superficial inspection of the crash site on Saturday before firing warning shots when two Ukrainian members of the group attempted to study wreckage.
On Tuesday, CBS News correspondent Mark Phillips watched as the three Malaysian Airlines investigators, accompanied by observers from the OSCE, took the first steps toward meticulously documenting the wreckage of the Boeing 777.
Phillips said the team took notes and photos of the debris, and looked visibly shocked as they began to take in what is the world's largest crime scene. But the clues to the crime and who committed it laid scattered across farmland and villages for days by the time those first investigators arrived, and it was far from the ideal, uncorrupted body of evidence they encountered.
An OSCE official, Michael Bociurkiw, told CBS News the handling of the crash site has been "invasive."
"I wouldn't want to use the word 'tampering' but from day one our initial observation - significant observation here - is that there's been no perimeter security...and one would expect that immediately to happen in this type of tragic incident," Bociurkiw said. "We've taken photographs and we'll compare them to photographs from the first days we were here and see if there are noticeable differences."
Bociurkiw said there even appears to be a "piece hacked out of" the tail of the plane.
The OCSE official said they have no idea what happens to the crash site itself at night because they are only around to observe during the day.
The plane's black boxes will be examined by U.K. air accident investigators, Britain's prime minister said Tuesday.
British experts at the Air Accidents Investigation Branch will retrieve data from the flight recorders for analysis, following a request from the government of the Netherlands, David Cameron said on Twitter.
Iow Tiong Lai, minister of transport in Malaysia, said it was "normal procedure for black boxes to be sent for analysis to the nearest laboratory authorised by the International Civil Aviation Association."
The experts expect to download all the information within 24 hours of retrieving them, a Department of Transport spokesman said. They will not publish their findings but will pass them on to Dutch authorities, who will then decide what information can be released.
The Obama administration said Tuesday it would present data from the U.S. intelligence community laying out what's known about the Malaysia Airlines plane that was shot down in Ukraine.
White House spokesman Josh Earnest said the intelligence community will have some additional data to present later in the day. No additional details about what would be released were available.
Earnest said the U.S. welcomed the news that most of the remains of the 298 killed have been handed over to authorities and the black boxes were transferred to Dutch and Malaysian authorities.
But he said the U.S. still hasn't seen the level of cooperation from Russia and pro-Russian separatists that it wants to see. He said international investigators led by the Dutch still need full and immediate access to the crash site.
Meanwhile, President Barack Obama visited the Netherlands Embassy in Washington and signed a condolence book for those who were lost. He said he wanted to "assure the Dutch people that we will work with them to make sure that loved ones are recovered, that a proper investigation is conducted and that ultimately justice is done."
Out of the 298 passengers and crew killed on the flight from the Netherlands to Malaysia, the Netherlands was the hardest hit nation, losing 193 citizens.