(S (S (S (BASENP (DT The) (NN letter)) (VP (VBZ comes))) (SBAR (IN after) (S (BASENP (NNS police)) (VP (VBD foiled) (NP (NP (BASENP (DT an) (JJ alleged) (NN attempt)) (PP (IN by) (BASENP (NNS terrorists)))) (S (VP (TO to) (VP (VP (VB blow) (PRT (RP up))) (NP (BASENP (JJ several) (NNS planes)) (VP (VP (VP (VBN traveling) (ADVP (RB mid-air))) (PP (IN from) (BASENP (DT the) (NNP United) (NNP Kingdom)))) (PP (TO to) (NP (BASENP (DT the) (NNP United) (NNPS States)) (PP (IN of) (BASENP (NNP America))))))))))))))) (PERIOD .))