(S (S (PP (VBG According) (PP (TO to) (BASENP (DT a) (NN police)))) (S (S (BASENP (JJ official) (NNS authorities)) (VP (VBD had) (VP (VP (VBN taken) (BASENP (DT the) (NN threat))) (ADVP (RB seriously))))) (COMMA ,) (SBAR (IN even) (SBAR (IN though) (S (S (BASENP (DT no) (JJ dangerous) (NNS substances)) (VP (VBD had) (VP (VBN been) (VP (VBN found) (PP (IN on) (BASENP (NN board) (DT the) (NN plane))))))) (CONJP (COMMA ,) (CC and)) (S (BASENP (NNS passengers)) (VP (VP (VBD had) (RB not)) (VP (VBN been) (PP (IN in) (BASENP (NN danger))))))))))) (PERIOD .))