(S (S (BASENP (DT This) (NN case)) (VP (VBZ comes) (PP (IN after) (NP (BASENP (DT an) (NN incident)) (PP (IN on) (NP (BASENP (NNP December) (NN 25)) (SBAR (WHADVP (WRB when)) (S (NP (BASENP (NNP Umar) (NNP Farouk) (NNP Abdulmutallab)) (PRN (COMMA ,) (BASENP (DT a) (JJ Nigerian) (NN national)) (COMMA ,))) (VP (VBD attempted) (S (VP (TO to) (VP (VP (VB bomb) (BASENP (DT an) (NN airliner))) (PP (IN with) (NP (BASENP (NNS explosives)) (VP (VBN concealed) (PP (IN in) (BASENP (PRPD his) (NNS underpants)))))))))))))))))) (PERIOD .))