(S (S (SBAR (IN Although) (S (BASENP (NN nobody)) (VP (VBZ has) (VP (VP (VBN claimed) (BASENP (NN responsibility))) (CC or) (VP (VBN been) (VP (VBN arrested) (PP (IN for) (BASENP (DT the) (NN airport) (NN attack))))))))) (COMMA ,) (S (BASENP (NNP Markin)) (VP (VP (VBD told) (BASENP (NNS reporters))) (SBAR (S (S (BASENP (JJ several) (NNS people)) (VP (VBP have) (VP (VBN been) (VP (VP (VBN brought) (PRT (RP in))) (PP (IN on) (NP (BASENP (NN suspicion)) (PP (IN of) (S (VP (VBG planning) (NP (BASENP (DT an) (NN attack)) (PP (IN on) (BASENP (NNP December) (NN 31))))))))))))) (COMMA ,) (SBAR (IN while) (S (BASENP (NNS others)) (VP (VBP are) (VP (VBG being) (VP (VBN sought))))))))))) (PERIOD .))