And senior Malaysian government officials told CNN last week that authorities have found nothing about either of the pilots to suggest a motive . NEW : The search is `` the most difficult in human history , '' China 's Jim Clancy says . `` We will not rest until answers are indeed found , '' Australian PM says . Malaysian ambassador : Focus moves due to searchers `` eliminating areas '' Official : All up to eight passengers have been cleared of hijacking , psych issues .
NEW : The search is `` the most difficult in human history , '' China 's Jim Clancy says . `` We will not rest until answers are indeed found , '' Australian PM says . Malaysian ambassador : Focus moves due to searchers `` eliminating areas '' Official : All up to eight passengers have been cleared of hijacking , psych issues .