Police are also investigating the cargo

Police are also investigating the cargo and the food served on the plane to eliminate possible poisoning of passengers and crew, he said.
The search for the plane began over the Gulf of Thailand and South China Sea where the plane's last communications were, and then shifted west to the Strait of Malacca where it was last spotted by military radar. Experts then analyzed hourly satellite "handshakes" between the plane and a satellite and now believe it crashed somewhere in the southern Indian Ocean.
A search there began just over two weeks ago, and now involves at least nine ships and nine planes.
The current search area is a 221,000-square-kilometer (85,000-square-mile) patch of sea roughly a 2?-hour flight from Perth. The focus of the search has moved several times as experts try to estimate where the plane is most likely to have landed based on assumptions on its altitude, speed and fuel. Currents in the sea are also being studied to see where any wreckage is most likely to have drifted.
Angus Houston, the head of a joint agency coordinating the multinational search effort out of Australia, said no time frame had been set for the search to end, but that a new approach would be needed if nothing showed up.
"Over time, if we don't find anything on the surface, we're going to have to think about what we do next, because clearly it's vitally important for the families, it's vitally important for the governments involved that we find this airplane," he told Australian Broadcasting Corp. radio.