Chinese authorities say they have found no links to terrorism in their review of all of the 153 Chinese nationals on board missing Malaysian Airlines flight MH 370.
China said it has deployed 21 satellites to help in the effort to find the vanished Boeing 777 commercial airliner that continues to baffle investigators and leave the family members of those on board increasingly desperate for answers.
Chinese authorities said they are searching a corridor of China's southwestern territory for any signs of the plane.
It is believed the jet could have headed in a northwesterly direction up through Burma, China and as far as Kazakhstan or taken a southwesterly arc to the Indian Ocean. Investigators believe the plane was deliberately diverted, but by whom and for what purpose remains unclear.
For its part, China's Ambassador to Malaysia Huang Huikang told reporters in Kuala Lumpur Tuesday that there is nothing to suggest the Chinese passengers on the flight were to blame.
"China has investigated the backgrounds of all Chinese passengers on board the missing Malaysia Airlines flight MH 370, and has found no evidence suggesting they are linked to destructive behavior on the aircraft. So we can rule out the suspicion that Chinese passengers are linked to a terror attack or destructive activities on the missing plane," he said.
In their quest to find more answers about what may have happened to the plane, investigators are looking into the backgrounds of all of those on board, including the flight's captain, co-pilot and crew. Authorities say that whomever took control of the plane had a deep knowledge of the jet and its systems.
Ambassador Huang said experts and security officials from China have been helping out with the investigation since shortly after the plane went missing in the early hours of March 8. However, what China's review of its radar data has uncovered remains unclear.
Publicly reviewing radar data has already proven to be a particularly touchy process because it can reveal countries’ air defense capabilities.
Shortly after MH 370 took off from Kuala Lumpur, investigators believe someone on board turned off equipment that identifies the plane to civilian radar. Malaysian military radar tracked an unidentified plane back across the peninsula, but no effort was made to confirm whether it was flight MH 370. It was not until a week later when Malaysian authorities confirmed that the unidentified plane was the missing jet.
From the area off Malaysia's west coast it is believed the plane could have flown either north or south.
James Nolt a senior fellow at the World Policy Institute said that like most developed countries China has air defense radar that can detect planes at mid to high altitude. He said that it is very hard for a plane to approach at that altitude and go unnoticed.
"However, radar follow straight lines, so if a plane is flying very, very, low, especially in an area that is mountainous then the radar would be blocked and would not necessarily be able to detect a low flying plane, particularly if it were following in the shadows of mountains or terrain obstacles like that," said Nolt.
Mountain ranges in southern China could provide such cover for a plane to fly into the country's airspace undetected, but Nolt says he believes it's unlikely the plane could have done that without someone noticing.
"Most countries in the region have fairly sophisticated radar systems, and air defense systems. I would be somewhat surprised if the airplane flew for any distance over land, I think my own belief is that it is more likely that it suffered some mishap over the ocean because it would be less likely to be detected if it flew primarily over the ocean," Nolt added.
Twenty-six countries are involved in the search, which now includes water and land in 11 countries and spans more than seven million square kilometers. Australia says it has narrowed its search somewhat based on new satellite data and water movements in the Southern Indian Ocean. The area it is searching in, however, is still roughly the size of Spain and Portugal combined.